This has been an issue for me as well. It's not a power issue as I have more than enough there too. It's not the fact of not having the updated drivers either.
I spent the first 2 months trying to fix it and it will still randomly happen. I have used winxp pro 32 and 64bit os's as well. (Neither would give me the set affinity option btw)
I have AMD KN8 SLI FX55 , 4 gig ram, 2x geforce 5500 gt's in sli mode, 600w supply, 32" lcd monitor, 2 sata hd's (Of which the second was solely used for EQ and nothing more than needed to try to fix this problem) etc.
Nothing I have done/found/had checked by "experts" has eliminated the problem. I have ran all the mem tests/vid tests etc.. does really well on them actually)
What I do now to give me more uninterrupted play time is to reduce to 2 accounts and run 2 others on 2ndary pc. I was able to do four accounts on main pc when I added the other HD w/only software on it needed to play eq. I would still get crashes though, just less often. Blue screen at times, other times just freezes.
I have spent countless nights just reading the different sites and other's issues.
As I said, what has worked out for me as being the most reliable is just only playing 2 accounts(3 is still ok, but I just expect trouble) and using my 2ndary or 3rd pc for the others. I dont really like that but its what I've had to "settle" for. Just less aggravation and headaches. I do wish there was a simple fix though, I just haven't seen it.