Hi guys. Last month when I was using the RC5 CD, I had a problem where I could not boot into a computer using the UBCD. The computer, an HP a1000y, had only an unformatted (raw) Maxtor DiamondMax ATA/133 8MB Cache 7200rpm HD attached to it. The UBCD would say 'The file dac2w2k.sys is corrupted. Press any key to continue.' followed by a reboot.
I suspected the problem wasn't with the computer because I always boot variants of PE off it with no problem. And I have successfully booted RC5 from the computer, but not with the maxtor hard drive attached. So after checking everything, and trying a few more times, I thought maybe it was a drive problem, and used a diff ribbon & power connector. Still won't boot.
Then I searched this forum, and then google, but I couldn't find anything similar (most of what I read concerned RAID cards/drives/etc). So then I think to myself, maybe it's the cd, maybe I scratched it or something. So I figure I'll try with another drive I know that works, a western digital. So I connect that. But I didn't unplug the Maxtor. Weird thing is that now UBCD boots, and I can access the maxtor in disk manager, disk investigator, etc.
I could reproduce the initial problem by disconnecting the Western Digital. I don't believe this to be a UBCD problem, although I was unable to test booting with other PE builds. It was probably a motherboard problem or a microsoft problem. And no, I do not have a RAID controller or anything of the sort (that's what dac2w2k.sys is for, apparently).
So if anyone ends up searching this board for a dac2w2k.sys problem with a similar configuration, I hope this helps.
And FYI - I had the western digital set as master and maxtor as cable select on the first channel. I mention this because I'm just now thinking maybe you could improve your luck with some combination of master/slave/cable select settings.