So I have an Alienware Aurora, nothing special.

I'm not entirely sure how long I've had it, somewhere around 2-3 years I would say, but lately it's been acting funny.

When I start it up it runs smooth, fine. Loads everything fast as it always has, but as time goes on it gets slower.
Sometimes to the point where I can't even close games without it just locking up. But if I restart my computer, it's fast again. I'm not talking about internet things only, I mean opening anything, folders, downloaded movies, Program Files, anything.
I've only talked to one friend about this, and he said it sounded like I had an infinite process running that was eating memory, but I don't.
I've checked and couldn't find anything running other than the things I have open. Does this sound familiar to anyone?

I'm getting really tired of needing to restart my computer ever couple hours so I can actually do things on it.

Really anything will help, thanks in advance.