Hi, have you install a codec pack?
If the answer is yes, then uninstall it and install only the codecs you need (read
BSPeter's
"READ THIS FIRST BEFORE POSTING" post items 1, 3 and 4)
If not, maybe you have installed another codec that now has problems, try to uninstall and then reinstall it and the problem will be fixed..
Otherways, I think the only other alternative is to re-register quartz.dll