My machine:
Athlon 1.2 Ghz, 256 megs RAM, TNT2, WinTV PCI, 20 gig on ATA/66 on mobo + 60 gig HD on ATA/100 PCI card, Philips PSC704 sound card

Using VirtualDub, I can capture at 352x480 (for example) in Preview mode. Frames are dropped because of the CPU having to blit in the lines above 240, but I do get sound.

When I switch over to Overlay mode and capture at 352x240, the video looks great, both on screen and in the resulting AVI file. VDub says I am getting audio (44 Khz, 16 bit), but when I play back the AVI file there is no sound at all.

Any ideas?

Preview mode = dropped frames (sometimes alot) and sound
Overlay mode = good video but no sound