Have you ever noticed how your computer seems to slow down over time? It's not your imagination. PCs build up electronic gunk in their system overtime as you use them. And just like the radiator in your car, a computer needs to be flushed out periodically to maintain its optimum performance.

Doing this can be a little tricky, however. So to help keep your machine humming along, we've compiled this list to help you do just that (no degree in Computer Science necessary):

Clean Your Registry - Once you've installed and uninstalled several applications, the registry tends to fragment, which can slow down your system. And if you're like most people, you've never touched this part of your system—and with good reason. Blindly attempting to edit registry values like "HKEY_CURRENT_CONFIG" isn’t advisable. Deleting or changing the wrong thing could cause applications—even your operating system—to stop working altogether.

But, ignoring the problem isn't the best answer either. So this begs the question, what can you do?

Special registry cleaning software can remove all the fragmented and missing files, so that only what needs to be in the registry stays there. In short, the right app can toss out all of the junk. Your computer then won’t need to sift through a mountain of garbage to find what it needs, leaving you with a faster, more stable machine. Just make sure the software you use is up to the task. As we noted, one wrong move can wreck your machine. Only use registry cleaners from an established, reputable company—no sketchy freebies.

Defragment your Hard Drive - Think of your main drive as a filing cabinet, offering fast access to folders with easy to find information. But what happens over time when folders invariably wind up crammed here and there? It isn't as easy to use, taking much longer to locate the correct files over when it was new and well organized.

To help speed up your drive, run a defragmenter. One is already likely installed on your computer. In Windows, just perform a search for it under "System Tools." A word of warning, though: Depending upon the capacity of your drive, and how badly it’s fragmented, you may need to wait a long time for your drive to fully defragment. With some defragmenters, it can take all night (yes, that long!).

Organize your Startup Programs - As the name implies, your Startup Programs are those applications that load and start automatically when you boot up your computer. The more you have active here, the longer it will take before you can start using your system.

Check to see which startup programs you really need and remove the ones you don't. Many times, software companies will place nonessential applications here to check on updates or inform you of promotional offers. Feel free to jettison those. The fewer you have in startup, the faster your machine will boot.

Consider adding more memory - RAM is now dirt cheap and it's easy to install, too. If you've been squeaking by with one gigabyte of memory, adding just one more stick can produce dramatic speed gains in your machine.

Just be sure to consult with the manufacturer before you purchase your new memory, as not all RAM is created equal. Simply tell them the type of computer or motherboard you have, and they will be able to point you in the right direction. But if you'd rather face a root canal than remove the case of your computer, your local computer repair shop will be happy to help, too.