[Wlug] add memory, loose sound?

I just added 128 MB of memory to my Dell Optiplex GX1, and now my sound card (on motherboard CS 4236) is no longer recognized. It's possible that I did something bad to the motherboard when inserting the memory cards. Or, is there any way that adding memory (now 128 + 128 + 64) could disable the sound? TIA, Bill