9800AIW to 8500DV or other way round won`t go.

[SHISH]

Here`s a good one.
I wanted to borrow a 9800AIW from one of my systems for a while so tried to replace it with a spare 8500DV.
Win XP SP2 says no way Hose and refuses to boot past the first flicker of the XP screen.
Best I can get is a blue screen (very fast) and a continuous reboot.
Used the recommended methods and also tried DC Pro.
Reset bios and switched off system restore, killed windoze sfc.
Tried other way round and same thing happened in another otherwise identical system.
Had a couple of 9700AIW (Canadian tuners for some reason so being RMAd) and none of the combinations, on identical boards and windoze, seem able to be swapped without a complete reinstall of XP.
What I can do, is get system going with a pci vga card or an old 7200 non AIW, but plug a new AIW in that`s diferent to the original install and it`s no go even if you`re not booting from it.
Thinking maybe XP is still replacing the system files on reboot but can`t seem to stop it.
Wish we had old system and could pre load a particular card but that`s a no no in XP now as well as drivers seem to be all in one and the list of video cards is no longer in existence due to plug and play.
Out of curiosity, I booted up an old machine on Win 2K and had no problems at all.
Anybody had this problem or found a solution.
Any video wizzards hangin out here?

[SHISH]

Solved it.
As I suspected, Windoze was replacing the drivers and DCPro wasn`t getting that location.
Despite switching off system recovery, there is still a repair folder and it is used to replace removed drivers even when you uninstall a card first.
Seems Windoze now doesn`t just keep a standard driver, it keeps the last driver or the first driver, not sure which, and insists on reinstalling it like it used to with the standard vga one. And if you then switch from one of the, now, two types of wdm drivers, you get the wrong one back in and it crashes out right where it loads the wdm drivers in XPs startup phase.
Just wiped all the ATI drivers from the win\sys32\drivers\repair\* folders and it went back to normal behaviour of actually looking for a default driver after loading basic vga one in.
Next problem????? Dunno, with complex drivers nowadays there`s always gonna be one I guess.