I've been around this forum for ages now, but I've only just got around to setting up a Giga system today - till now I've been a Kontakt man.
So I installed GS3.04 (I know there are updates, but I don't accept that a version should be so unstable as to not boot at all, so I'd rather fix the problem and then update) on a brand new PC (P4 3Ghz, 2GB DDR RAM), with absolutely nothing else on it (apart from WinXP and Nero Express) and went through the whole registration thing. Everything seemed to be fine - I got a screen saying, 'Congratulations, you are now a registered user of Gigastudio.'
Then I tried actually starting GS. Nothing unexpected at first. It warned me that GS would be forced into Rewire mode, since I don't have a soundcard fitted (I intend to use Gigateleport, which apparently doesn't require soundcards on the remote machines). Then it updated its sound database. Then it promptly crashed my machine to a BSOD, with the message, 'IRQL_NOT_LESS_THAN_OR_EQUAL' This now happens every time I try to start GS.
I already searched here, and found that someone had had the same problem, but I'm not sure I'm clear how that thread ended. Some people were suggesting that his soundcard was the problem, which clearly can't be the case here. Some people seemed to suggest that memory tweeking might help, but I don't fully understand how poor memory distribution would stop GS from simply booting. Another suggestion was that GS had dumped its content into a drive that was just a cache drive, and thereby filled it - but I didn't let GS install its content at all.