A pair of nasty CPU flaws exposed this week have serious ramifications for home computer users. Meltdown and Spectre let attackers access protected information in your PC’s kernel memory, potentially revealing sensitive details like passwords, cryptographic keys, personal photos and email, or anything else you’ve used on your computer. It’s a serious flaw. Fortunately, CPU and operating system vendors pushed out patches fast, and you can protect your PC from Meltdown and Spectre to some degree.

It’s not a quick one-and-done deal, though. They’re two very different CPU flaws that touch every part of your operating system, from hardware to software to the operating system itself. Check out PCWorld’s Meltdown and Spectre FAQ for everything you need to know about the vulnerabilities themselves. We’ve cut through the technical jargon to explain what you need to know in clear, easy-to-read language. We’ve also created an overview of how the Spectre CPU bug affects phones and tablets.

The guide you’re reading now focuses solely on protecting your computer against the Meltdown and Spectre CPU flaws.

How to protect your PC against Meltdown and Spectre CPU flaws

Here’s a quick step-by-step checklist, followed by the full process.

Update your operating system
Check for firmware updates
Update your browser
Keep your antivirus active
First, and most important: Update your operating system right now. The more severe flaw, Meltdown, affects “effectively every [Intel] processor since 1995,” according to the Google security researchers that discovered it. It’s an issue with the hardware itself, but the major operating system makers have rolled out updates that protect against the Meltdown CPU flaw.

Microsoft pushed out an emergency Windows patch late in the day on January 3. If it didn’t automatically update your PC, head to Start > Settings > Update & Security > Windows Update, then click the Check now button under “Update status.” (Alternatively, you can just search for “Windows Update,” which also works for Windows 7 and 8.) Your system should detect the available update and begin downloading it. Install the update immediately.

You might not see the update, though. Some antivirus products aren’t playing nice with the emergency patch, causing Blue Screens of Death and boot-up errors. Microsoft says it’s only “offering the Windows security updates released on January 3, 2018 to devices running anti-virus software from partners who have confirmed their software is compatible with the January 2018 Windows operating system security update.” Security researcher Kevin Beaumont is maintaining an updated list of antivirus compatibility status. Most are supported at this point. If your AV isn’t supported, do not manually download the Meltdown patch unless you turn it off and switch to Windows Defender first.

But machines with compatible antivirus still may not automatically apply the update. If you’re sure your security suite won’t bork your system, you can also download the Windows 10 KB4056892 patch directly here. You’ll need to know whether to grab the 32-bit (x86) or 64-bit (x64) version of the update. To determine if your PC runs a 32- or 64-bit version of Windows, simply type “system” (without the quotation marks) into Windows search and click the top listing. It’ll open a Control Panel window. The “System type” listing will tell you which version of Windows you’re running. Most PCs released in the past decade will be using the 64-bit operating system.

Apple quietly worked Meltdown protections into macOS High Sierra 10.13.2, which released in December. If your Mac doesn’t automatically apply updates, force it by going into the App Store’s Update tab. Chromebooks should have already updated to Chrome OS 63 in December. It contains mitigations against the CPU flaws. Linux developers are working on kernel patches. Patches are also available for the Linux kernel.

Now for the bad news. The operating system patches will slow down your PC, though the extent varies wildly depending on your CPU and the workloads you’re running. Intel expects the impact to be fairly small for most consumer applications like games or web browsing, and initial testing supports that. Our FAQ digs into potential PC performance slowdowns from the patches. You still want to install the updates for security reasons.

Check for a firmware update

Because Meltdown’s CPU exploits exist on a hardware level, Intel is also releasing firmware updates for its processors. “By the end of next week, Intel expects to have issued updates for more than 90 percent of processor products introduced within the past five years,” it said in a statement on January 4.

Actually getting those firmware updates is tricky, because firmware updates aren’t issued directly from Intel. Instead, you need to snag them from the company that made your laptop, PC, or motherboard—think HP, Dell, Gigabyte, et cetera. Most prebuilt computers and laptops have a sticker with model details somewhere on their exterior. Find that, then search for the support page for your PC or motherboard’s model number.

Update your browser

You also need to protect against Spectre, which tricks software into accessing your protected kernel memory. Intel, AMD, and ARM chips are vulnerable to Spectre to some degree. Software applications need to be updated to protect against Spectre. The major PC web browsers have all issued updates as a first line of defense against nefarious websites seeking to exploit the CPU flaw with Javascript.

Microsoft updated Edge and Internet Explorer alongside Windows 10. Firefox 57 also wraps in some Spectre safeguards. Chrome 63 made “Site Isolation” an optional experimental feature. You can activate it right now by entering chrome://flags/#enable-site-per-process into your URL bar, then clicking Enable next to “Strict site isolation.” Chrome 64 will have more protections in place when it launches on January 23.

Keep your antivirus active

Finally, this ordeal underlines how important it is to keep your PC protected. The Google researchers who discovered the CPU flaws say that traditional antivirus wouldn’t be able to detect a Meltdown or Spectre attack. But attackers need to be able to inject and run malicious code on your PC to take advantage of the exploits. Keeping security software installed and vigilant helps keep hackers and malware off your computer. Plus, “your antivirus may detect malware which uses the attacks by comparing binaries after they become known,” Google says.

PCWorld’s guide to the best antivirus for Windows PCs can help you find the best option for your setup—though note the section above where we discuss the compatibility issues some AV programs are having with the new Windows patch.

Teach you how to replace your computer’s internal power supply component.

Step 1.Find the power supply.

This supplies power to the other components, which is why it has so many wires coming out of it. It is usually positioned at the back top corner of the computer case. The power supply has a fan built into it to keep itself and the computer cool.

Step 2.Get into the tower.

To get into the tower, you will have to remove the panel which is on the right hand side when viewing the tower from the back. Open this side of computer case by removing the screws at the back of the tower which are holding it in place. Then simply slide the panel off.

Step 3.Disconnect the power cables.

Cable from the power supply should be connected to each component requiring power. These cables are easy to disconnect simply pull out the plugs from sockets on the back of the components. The plug and socket on the motherboard are a different shape from the normal type, but it should come out just as easily. It may be a good idea to write down how many sockets were disconnected so you can make sure they are all reconnected later with the new unit.

Step 4.Remove the power supply.

Remove the screws at the back of the power supply unit while supporting it with one hand. Once the screws are undone it should be easy to slip the old unit out of the tower.

Step 5.Power cable connection.

Screw in new drive then connect the power cables to every component that was originally connected. Remember if any components are left unconnected they will not work.

Step 6.Get it going again.

Switch the computer on, if all the components have been connected you should be ready to go.

Q&A

My PSU is on the top front of my case. Can you help me to remove it? It comes with a case so it’s generic?

Check for screws on the outside of the case, and inside of it. See where the PSU is being held into the case. I cannot help that much as I do not know what case you have.