Do I need a new computer?

[Kerensky287]

Now, to preface this: I play a lot of games. I often play them online. I'm usually a good sport when I lose, but when I lose due to issues I feel are out of my control (imbalance, lag and performance issues, etc) I get a little pissed. I AM coming to post this after a 3-game losing streak on Starcraft 2 due entirely to my computer deciding to freeze during micro-heavy moments.

So my computer is around... I guess 4 or 5 years old now. At the time of purchase it was fairly top-of-the-line, and even now I don't think I've found a game that it can't at the very least start up. But lately I've been having a ton of issues with slowdown in ALL games, not just newer ones. Having no knowledge of computers, I'm curious - is the computer just aging poorly? Do I have some malware or something in my computer? Or is it just time I bought a new one?

My computer's specs (obviously it's had some parts updated since I bought it, but nothing huge):

Pentium 4 CPU 2.60GHz (single-core)
1 GB of RAM
NVIDIA GeForce 7600 GS (256mb)
...Some kind of motherboard that I don't know how to check.

Any recommendations? Any help would be appreciated. Thanks in advance!