Hi there. I recently reformatted my hard-drive and am having some problems playing video files that contain audio.
First of all I could play audio-less video files, and I could also play video-less audio file, but I couldn't play a file which was a combination of the 2!
When I tried to play such a file the PC wouldn't crash, just slow RIGHT down so the PC was unusable, until I hit ctrl + alt + delete and stopped the process.
Then I installed a bunch of codecs (including the K-lite codec pack) and the problem was sorted BUT now I just can't SEE the video. I can hear the audio, and the PC doesn't slow down like before, just the video itself doesn't seem to be playing!
I'm pretty sure it's nothing to do with the drivers as i've installed the latest ones 3/4 times now.
Sorry, you mentioned drivers at the end of your first post eh... Does the same thing happen regardless of what media player you use? Are you using a dedicated graphics card or on-board video hardware? Check there are definitely no conflicts in device manager, and that your graphics card hardware acceleration is set at maximum (control panel/display/advanced/troubleshoot).
The conflict(s) I was referring to would be seen in device manager, as yellow exclamation marks or red crosses against the problematic device. Unlikely to be any problems but worth a quick look.
Re-install the basic set of Windows XP codecs if required, then try the Basic klite codec pack (too many codecs can be more problematic than none at all). If the codecs can't be found, the computer doesn't have any work to do, so there can't be any slow-down :S Folder names are unlikely to be the issue