Flash Video not playing to completion

I have a box that will not play flash video. Ran the flash uninstaller, manually edited the registry removing all references to flash or macromed folder, deleted system32\macromed folder, ran an XP repair, used firefox, IE and Avant, ALL had the exact same results!!!

youtube plays for 2 seconds, comcast news video plays 5 seconds. the download IS completing. I can drag the slider to a different location and it plays….for 2 seconds or 5 seconds depending on location. I am considering a complete fresh install of XP…my fear is the time that reinstalling will take to end with the same results.

Thanks