2nd Graphics Card Problems - HELP!

My new card arrived today.

I installed it, but my PC refused to boot. Everytime it got near the login screen the blue screen of death appeared:

So, thought there was an error with the card, so removed it and the blue screen kept coming up, even after several reboots.

I restored my computer to an earlier point in time, yesterday (neat feature, never used it before, works really well) and the PC is working fine now.

A few problems I thought might have caused this problem:

  1. Conflict between video cards? On my mobo there’s one PCI slot above the PCI-E 16x slot (which has my 8800GT in it). Should I install it on one of the other ones near the bottom?

  2. Driver install? Should I install the drivers before installing the card? Never needed to do this before, but should I do it now? Does it even need more drivers concidering I have nVidia drivers for my 8800GT and the latest nVidia control panel?

Also, here’s a photo of my motherboard from the manual (sorry coulden’t be bothered to scan it, so just took a photo of it instead):

Number 10, 11 and 12 are the PCIE slots and the two below are the PCI and there’s one more ablve the top PCIE slot. I plugged the card into the top one (also obstructed the fan on my 8800 a little).

Basically my sound card is in the PCI slot 2nd from the bottom, and I can’t really put the new graphics card in the very bottom PCI slot because it’s obstructed by the HDs in my PC (Dell decide to put them right at the bottom).