Seems like if it is working other than when using ICE, it may be just the driver, rather than a hardware issue... Have you tried to reinstall the appropriate driver and see if that works? On the other hand, ICE uses a separate bulb than normal scan operations, so it's possible the problem could be with that bulb specifically.
FWIW, when using ICE on medium format negatives at a fairly high resolution, I'll typically have about a 30-45 min scan time. The results are usually perfect mind you, even at 4800-9600 dpi, but the wait time is tiresome. If I'm scanning Large format the scans can take well over an hour, but I suppose an hour of ICE doing it's thing is better than the likely two hours sitting picking out dust in Photoshop. Dust and scratch removal is sometimes acceptable, but I usually find it removes much more detail than I'm comfortable with. I'd usually rather do it manually than use the D&S removal (at least for negatives)...
Anyway... maybe just give it some time... it may seems like nothing is happening, but the scanner is comparing the visible scan to the infrared scan, the processing can take quite a while.
-Jason