So you upgraded to Windows 7 but are as always having issues with Codec’s (A codec is the ‘decoder/encoder’ for a video or soundfile in a specific format eg. DivX or Xvid).
Under Windows Vista the Vista Codec pack seemed to work perfectly, but I was reluctant to install it on Windows 7 out of fear to create problems for H.264 (H.264 is now native to Windows 7, which was not the case for Windows Vista). However in the end I had to (too many things did not work without these codec’s), anyway it turned out that the Vista Codec Pack would not install on Windows 7, it cleverly detected that it was a new OS and pointed out that a new package was available here.
So all in all, my worries was laid to rest and I downloaded Windows 7 codec pack and everything was back to the old working state.
Do you need this codec pack? Well very likely not, most users can download the VLC player this player has build in most common codec’s and can thus play most video/snd files you get hold of, however if you need to do video conversion etc. then it is a different matter, Windows then need to be able to ‘understand’ the fileformat and this may ofthen require a codec. The rule should be, try VLC player, if its enough dont install anything more if not install the Windows 7 codec pack or Windows Vista Codec pack (also works for Windows XP).