Windows not booting with 2 CD drives (ACPI problem)

Small problem, annoying..

It's like this, my pc was working fine with temps around 40C but needed a good clean, so i did, stripped it all cleaned it all out made it look new, to my delight it brought the cpu temp from 40 to 34c,

I then format and install everything games etc, then i install advanced config (ACPI PC) or as some call 'ricky tweak'

My pc wouldnt boot windows up anymore, stalls just before the windows scroller shows, i tamper about abit taking stuff out, it then worked, i put stuff back in to find the problem, then i find it's the CD drives.

ok, they both work fine in IDE 2

BUT only one works on IDE1

I don't get it, everything worked fine before even with advanced config.

Also pc loads fine with uni processor on with IDE1 both drives work.

any suggestions?

edit, swapped the master and slave switches on the drives to check it wasnt a drive, and it only works on the master when its in IDE1 (remembering both drives work fine on IDE2)

It's not that big of a problem i could just use IDE2, but i dont get why they wont work on IDE1 anymore when they used to..

I don't quite understand why you changed the HAL after a fresh reinstall. If I understand correctly, Windows selected the ACPI Uniprocessor PC Hardware Abstraction Layer (HAL) over the Advanced Configuration and Power Interface (ACPI) PC HAL? If you need to specify a particular HAL before a fresh install, you can do so by pressing F5 at the "Press F6 if you have to install a third-party SCSI or RAID driver" blue screen. You can then use the up/down arrow keys to select the HAL of your choice. If you also need to load SCSI/RAID drivers, then immediately after pressing F5...press F6. You'll select the specific HAL, exit from that screen...then continue on in the setup until asked to insert a floppy containing your RAID/SCSI drivers.

You should see the following HAL's listed on the F5 screen...

ACPI Multiprocessor PC
ACPI Uniprocessor PC
Advanced Configuration and Power Interface (ACPI) PC
Compaq SystemPro Multiprocessor or 100% Compatible
MPS Uniprocessor PC
MPS Multiprocessor PC
Standard PC
Standard PC with C-Step i486
Other

How to force a Hardware Abstraction Layer during an upgrade or an installation of Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;299340

Thanks for ur help, but
I never knew about that, didn't think it would make much difference changing it in windows, so if i changed it before a fresh install on the part you said, everything should be ok?