Basically the problem is that whenever I open a game running in a window or do various other tasks, my ADSL modem desyncs and won't resync until I stop doing whatever i'm doing.
Things that have caused this to happen thus far:
Playing Neverwinter Nights in window mode (fullscreen mode has no problems)
A large Photoshop document
Uploading via Dreamweaver's ftp tool (other ftp tools work fine)
The thing is... i'm pretty sure this has nothing to do with my ADSL connection or the modem, as it also does this with a 56k modem. I have also tried using ADSL on another computer and it worked fine. The hard drive has been formatted recently so i'm also fairly certain that it's nothing to do with any installed software, so this leads me to believe that it's something to do with hardware (most likely the graphics card) or any drivers.
My computer's basic specs: (the one it doesn't work on)
Geforce FX 5200
The other computer's basic specs: (the one that it worked on)
Pentium 3 - 700mhz
Radeon 64mb (i forget the exact type)
Has this happened to anyone else? Does anyone have any ideas as to what I should do?