Not necessarily Vista/Seven are a lot more "sensitive" to bad memory than XP was, it wouldn't be the first time.

Even if it's not as accurate as Memtest you can try Seven builtin memory test utility. It's somewhere in the boot options.

I'm not sure if you're making a joke flying much too high over my head for me to catch it, or if you really think that's what I meant.

In the latter case:
If one is wary of "unofficial sources" (ie. unwilling to pirate), one can download Windows 7 Service Pack1 and use that in combination with an existing RTM disc to create an installation disc with SP1 built in.

("sorry - wut?" is a completely acceptable reply, as I chose not to go into technical detail before such help was requested).

In the first case:
Forget this post.

Oh I'm terribly sorry I thought you're talking about win XP there, stupid me.
*bangs his head against a wall*

It was the latter...;o)

even that you can create an integrated pack using software like nlite

Yes, or skip nlite if your main concern is the service pack itself, rather than all updates after it. All Windows service packs since Windows 2000 have built-in functionality for slipstreaming.

Well... Yeah, but you can't really get XP from official sources anymore. Unless you can download it from the .. universities .. cooperative ... thingy.

Edit: Oh I also found out why it was so ... weird. I've done some tweaking to the system and totally didn't realize it up until now. I often kill time by tweaking performance and then fixing all I have broken :D

MSAA :P
you can still pick up OEMs of XP they're just hard to find

I'd just skip nlite, it was always slightly dodgy and its successor vlite is complete shit. All the cool kids build slipstream OS installs with RT7Lite nowdays
I keep saying how great I am and you just keep doubting me. I'm getting it tattooed on the inside of your eyelids next time.

So was it drivers then?