It wasn't their solution exactly, but some of the things they suggested led me to it. They recommended various things:
re-installing ALchemy from CD, re-downloading latest drivers, trying the card in a new system.
What I did:
Insert CD, go to "install" but instead "repair" ALchemy.
However, I'm sorry to say, this did not last long. After a short while, I now have 2 more issues:
1) No sound at all, everything under options/sound is greyed out and I can't check/uncheck anything (disable sound is checked).
2) ALchemy won't start at all. If I double click it, nothing happens. Checked the task manager, it doesn't even appear briefly.
If anyone knows the solution to 1), I'd love to hear it. I didn't do anything to my settings other than repair ALchemy, and the problem didn't start right after that anyway.