I've lately been recording old reel-to-reel tapes onto the PC
thru the Line-In connector of my on-board" sound card. Then
disaster struck (system files corrupted!) and I had to format
C: and rebuild the system, including all the original
drivers from the original CDs. All went well, except ...

Sounds (Start/controlpanel/sounds) could not be heard thru
the speakers UNLESS I muted Line In on the Volume Control.

Audio CDs could not be heard thru the speakers UNLESS I
muted Line In on the Volume Control.

But nothing could be heard coming from tape drive thru Line In
whether muted or not.

I rebooted, killed the onboard sound card, and installed a
separate sound card. Now all works great. And I can continue
to record tapes thru Line In AND play sounds while Line In
is not muted.

So ... what happened??

chuck