computer is not responding properly.

This is a lot like saying that a body part of yours hurts, but not saying how bad the pain is, where it is, how long it's been bothering you oh and by the way, you forgot to mention that you were hit by a bus yesterday. Plus you're not telling us your gender or age or whether that mysterious body part has ever hurt you before.

Yeah, this question is that vague.

Standard response - check your computer for spyware, run a virus scan, and go to an earlier restore point. Anything more specific than that, you'll have to give us more specificity, too.

Time to meet Mister Google, and search for answers to your problem with some specifics. "Personal computer" is too vague, because the answers are different depending on whether you have an Apple Mac, a Dell or a PDP-8.

One of the most common causes is disk fragmentation, which can easily be solved by "defragging." Again, ask Mister Google for specifics based on your computer type. Some other suggestions from PC magazine:
http://www.pcmag.com/slideshow/story/315484/10-tips-to-speed-up-your-pc