I tried downloading the ECS K7SOM 7.5c updated BIOS from http://www.wimsbios.com/files/vgabiospatched/bios.jsp, but the downloaded zip does not extract. The error message varies depending on the program I use to unzip it.
No problem with unpacking here. Delete the file, download it again and try to unpack. If it still fails clear your browser cache and dwonload it again (it's possible the damaged file is "redownloaded" from the browser cache so still damaged).
I even tried downloading it from a different computer and it didn't work.
Tried it again right now and it extracted fine. I can't imagine what had gone wrong the previous times.
firefox will simply dump an incomplete file on your disk if the network connection between the original website and the last proxy in the chain is sufficiently bad. I think that's what happened.