I make a cap, right click on the file, check details audio shows up, video has frame and data rate but its shown as a unknown format.

I've installed and uninstalled the codec several times.
Tried different res's and bitrates. Its always unknown format.

How do I see if the codec is registered properly?

EDIT:
Using win98se

Exampte:
Audio Format: PCM,44,100 Hz, 16 Bit, Stereo

Video Format: 320 x 240, 1375 Frames, 29.971 Frames/Sec, 457 KB/Sec, Unknown Format