For the last three weeks to a month, whenever I play a video file, the video may play fine for anywhere between 1 and 10 minutes, then it slows down to playing a few frames, freeze a second or two, play a few more frames, freeze a second or two. This problem occurs no matter what media player I use (Media Player Classic, AlShow, Divx, Quicktime, etc). It seems to happen no matter what file I try to play. I have had various computer issues over the past year or so that will seem to somewhat resolve themselves after some tinkering (such as reinstalling programs like Firefox and Photoshop, removing Norton when it seemed to be corrupted, stopping programs running in the background, and trying to clean up junk on my machine). There always seems to be a new problem, though, and I've probably caused more problems than I've solved. My system is not the most up-to-date system, having a 350 Watt Power Supply on a socket 775 Motherboard and Celeron 2.4 GHz with 1GB Ram. I have tried playing the files from the USB drives as well as the internal PATA drives. It all plays the same.
I have tried various malware and spyware removal programs, replacing my codecs completely, shutting down services I do not need, cleaning my TSR programs that begin on start up, and doing multiple virii scans.
Any help the community can provide would be appreciated. I'm not adverse to reformatting and reinstalling Windows if necessary, but I know that can be a big deal and I'm not 100% sure where the problem is at this point (I guess I don't even know if it is a hardware or system problem or possibly both). Thank you so much for whatever help you can offer.