Intermittent Web

Ok. I have a problem that I just can't figure out. I have 2 computers. One of them is wired directly into a router. The other is using a wireless USB adapter.

For months, everything fine. Then I noticed that I would have intermittent loading of web pages on the wireless computer. Parts of the page would load, then stop, then continue, then stop...and so on. Results of online speed tests vary greatly where in the past, it would consistantly be in the 2500kbps range. Now I get nowhere near that.

First, I blamed the ISP. But the other computer is loading web pages without a problem and speed is fine. So I thought it was a wireless issue. I carried the other computer to the other room, wired it to the router (just like the other computer) same problem! After changing some settings as recommended by DSL Reports to no avail, I decided that I would restore my computer. So I cleared off my hard drive and reinstalled Windows XP. After installation was complete and before installing anything else, I tried the internet, and same thing!

The last thing I did was reset my bios to the default settings and that didn't work either. I can only think of a hardware issue, but I do not know where to start. Everything else on the computer seems to run fine. Does anyone have any ideas?