Fix a Slow Windows PC

 In Fix It




Just about anyone who uses Microsoft Windows has at some point or another reached the pinnacle of frustration and cried out “THIS COMPUTER IS TOO DAMN SLOW!”

For some people, this means “dealing with it” until they can afford a new computer, or they pay someone to come fix it. In most cases, there’s a few things that you can do to avoid having to shell out big bucks to get your computer speedy again, and sometimes computer slowness is more than just software problems. Let’s take a look at the common causes of Windows computers running slow and how you can fix them.

Why Your PC Sucks

Windows PCs use something called the Registry to keep track of all the settings for both the operating system and the different programs on your computer. It’s basically a giant database with a lot of entries called Keys. Sometimes these Keys point to file locations, and sometimes they point to other Keys, or sometimes they just contain data like how many seconds before your Start Menu opens after you click it.

If you uninstall a program and it doesn’t clean up after itself properly, your computer will spend time reading the leftover Keys. If they point to something that doesn’t exist, that’s a lot of valuable computer resources gone to waste.

Another reason your computer might suck is if your system doesn’t have a lot of free hard drive space. The computer uses a portion of the free space on your hard drive to create what’s called a Page File. The Page File is basically a temporary file that acts like extra RAM in your computer, called Virtual Memory. You might be getting messages that say your computer is running low on Virtual Memory if there’s something wrong here. Making space on your hard drive can help.

Solution: Install CCleaner (free, the donation link is listed first, then further down “download from” will get you the download if you don’t want to donate yet) from and run the Registry and Cleaner tools. The Cleaner tool will remove temporary files that you don’t really need. You can pick which to clean up or just let it run with the default ones checked. Run the Registry clean-up tool and tell it to fix any problems it finds. Most any computer will benefit immediately from these two tools.

Windows bugs are another reason a computer might run slow. There’s a bug with older versions of Windows like XP that an update was supposed to fix, where a process (a program that runs in the background) constantly pegged out at 100% cpu usage. It was actually tied in to the Windows Update service.

Solution: I always have to Google the solution to this, so I’m reproducing it here for easy finding. I am not the one who figured this out.

  1. Go to Start, Run. Type in “cmd” (without quotes) in the box and hit your enter key.
  2. Type in these commands, one line at a time, and hit enter at the end of each line. When you get to the lines that start with %windir%, you will have to also hit an OK button that will appear.

net stop bits
net stop wuauserv
rename C:\Windows\SoftwareDistribution C:\Windows\sdold

%windir%\system32\regsvr32.exe /s %windir%\system32\atl.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\jscript.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\msxml3.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\softpub.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\wuapi.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\wuaueng.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\wuaueng1.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\wucltui.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\wups.dll
%windir%\system32\regsvr32.exe /s %windir%\system32\wuweb.dll

net start bits
net start wuauserv
wuauclt /resetauthorization /detectnow

That should fix the slowness, or at the very least give you a little speed boost. Those instructions are non-destructive, you probably can’t break your computer from a typo doing any of that.

Start-up Items

A lot of computers (especially bought from stores like Wal-mart or Best Buy) come pre-loaded with a lot of bloated programs to make you think you’re getting extra value from your purchase. In reality, a lot of these programs you will never, ever use – but they still insist on starting when the computer loads up to your desktop.

If you follow the instructions above and have already installed CCleaner, you can look at the start-up items for your computer. It’s important to note that some start-up items are critical and should be left enabled. If you’re not comfortable, you probably shouldn’t mess with this yourself. However, if you look at the file location for the start-up item, you can usually tell if it’s important or if it’s something installed by your manufacturer that you don’t want or need to start when you first boot up.

If you’ve done all the above – go ahead and reboot your computer (turn it off and back on again). Your computer should run noticeably faster if your problem was software-related. CCleaner is also an excellent tool for getting rid of computer viruses and the places that they hide out when you’re infected. This is something I use at work almost every day and comes highly recommended.

Maybe It’s You

On older versions of Windows like XP, you may still have to “defrag” your hard drive. I found Disk Defragmenter under Start, All Programs, Accessories, then System Tools. You may choose to have it “Analyze” first, to see if you need to defragment – or more likely just choose to start defragmentation. It will analyze it first anyway and then defrag as much as it needs to do so. Defragging basically moves all the files on your hard drive from their physical locations to one section so that the drive heads have less distance to travel and theoretically this increases disk read time.

Or maybe it’s just you. You could be too impatient. Trust me, it happens. Your computer may actually not be as fast as you expect it simply because your expectations are too high. As Microsoft releases updates to Windows, the minimum recommended requirements can often change with these updates. If you bought a computer good enough for Windows Vista Home Basic, and you expect that 2 years later it’s still going to fly like it did the first day – or maybe you’ve wiped and re-installed Windows, and it was fine for a while, but then it got slow again? It’s because the Windows on your install disc is vanilla – it has no updates with it yet. As those updates download and install, your system will start to crawl again. You may need to legitimately look into getting a memory (RAM) upgrade.

My mother bought a Gateway laptop back in 2006 with Windows XP and it worked fine for a long while, but more recently it started to crawl. I put Windows 7 on it and had my parents order a memory upgrade to 2 gigabytes from its original 512 megabytes, and as expected it’s about 3-4 times faster. Check with your local PC shop or shop online and you will likely find a memory configuration tool that will show you the most amount of memory your computer can support.

I'm a 29 year-old blogger and tech support guy at a small university in the south. Technology makes me angry. I have certifications from Microsoft and Apple and I love Linux too. RAWR.
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Showing 2 comments
  • Janie Harrington

    Great article! Thanks for fixing my mom’s computer! I got the extra memory in the mail and I’m going to install it for her tonight. It already runs a LOT faster since you fixed that windows bug. <3

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