Audible click and then the video freezes

I have a pc with a Diamond Viper 550 video card, the latest driver for the Viper 550, the latest Windows Media Player, the latest DirectX and the video still freezes when I try to view videos or when I try to run the Diamond Update Wizard. There isan audible click from the PC when the video freezes. Where should I look next? This PC played videos before tech services at a private school reformatted the hard drive and reloaded Windows 98.