Why is everyone pointing out viruses, malware, and aging components? He clearly mentions that he's only running 1GB of RAM... you should all realize that as the bottleneck immediately, especially when he mentions running multiple programs as being slow.
It amazes me that people will jump in and suggest buying new hardware without having nearly enough information to answer the problem first... slowness when multiple programs are running doesn't mean you should just go out and buy some RAM! There's LOTS of things that could cause that. So, a few questions that will help narrow the problem down:
- What operating system are you running? Is it still the one that came with the computer (XP perhaps? Or Vista?)
- Are the games and applications that are running slowly now new, or were they running perfectly fine in the past and have suddenly started to slow down to unusable levels recently?
- Did the change occur suddenly or was it quite gradual over a period of time?
- Have you de-fragmented your hard drive and run chkdsk recently?
- Have you run memtest recently? If so was all the RAM good?
If you can answer all the above questions properly then people will be able to give much more informed answers as to what's going on.