improve performance

I am trying to improve the performance on a pc. It is running windows ME. The CPU speed is 800 MB and I believe it has 256 MB RAM and about 5 GB of hard drive space. It got hit by a virus a few months ago. I ended up reinstalling the OS from scratch. It runs ok now, but not nearly as fast as it has in the past, or as fast as you would think for such a pc. It is not quite a year old. Does anyone have any tips or suggestions to try? I’ve heard that recreating the swap file may help, but how do you do that? Thanks!