Buffering Is Very Slow

I have a Dell Dimension 8400 running WINXP Pro with 2G of RAM and a P4 CPU 3.4GHZ - it had been downloading video such as you tube just fine and now the buffering is so slow it is near impossible to watch video any more. The task manager indicates that the CPU is running well (not at full capacity) and the paging file looks good also. This system is wire connected to a cable modem via a linksys router. The laptop that I use wirelessly via this router operates fine, no lag at all. I run Firefox (latest version) and Norton 360 4.0. I have re-loaded N360, the ATI video driver and reset the paging file and video acceleration. Nothing has helped. Any ideas what else to look for??
Thanks, Bufferless in CT . . .

Not all video sites are equally "kosher", so you might want to check your computer for malware.
If you want to do so in this forum, please read this and after that post here.