PA321,
First, you should try an update your computer. At a minimum, you should load XP Service Pack 1a, any updates for Media Player, and any updates for your video card. Go to...
http://v4.windowsupdate.microsoft.com/en/default.asp
Click "Scan for Updates" and select the three things that I listed above. Do not select the others right now, but you should go back and download them later. If you are still having problems, then you probably have an older computer that was recently upgraded to XP. As a result, the hardware compression may not be capable of "keeping up." Try slowing down your hardware compression...
1) Go to CONTROL PANEL
2) Double-click DISPLAY
3) Click "Settings" tab of "Display Properties" dialogue box
4) Click "Advanced"
5) Click "Troubleshoot" tab of "<name of video card> Properties" dialogue box
6) Move the arrow from right to left (closer to "None")
Move the arrow one level at a time and try the video until the flicker stops. If this doesn't work, take your PC to your local computer geek and have them take a look.
R2