Recovering from a power surge; new vid card?

My building had a blackout 2 nights ago, and when the lights came back on, my GTS 8800 video card had issues.

My monitor displays a "no signal" message, but everything else seems to work right: the hard drive is loading at the same pace that it always has, the USB peripherals light up as if they are functional, & it's making all the right booting noises that it used to. I don't have a spare video card to swap out and check my system.

To get everything going again, I have the following questions:

1) Is it possible for a power supply to get damaged by a power surge/blackout so that it's not functioning at its listed specs? My expectation is that when confronted with surges/blackouts, power supplies either survive and work fine, or they burn out & die, with no middle ground.

2) If I'm wrong about #1, and a power supply can still work with diminished capacity, would a power-hungry video card like the GTS 8800 not produce any signal whatsoever if the power supply weren't up to par? Again, I'm thinking that this isn't the case, but I want to double-check.

Assuming that I need to replace the video card, I'm looking at the Radeon HD 4850 X2 2GB. It's essentially two video cards that are merged together, and work through one PCI Express slot, although it relies on ATI's Crossfire technology.

3) I currently run Windows XP 64; do I need to run Vista or Win 7 for Crossfire to work properly?

4) My motherboard is an ASUS P5B. It has the 965 chipset that supports Crossfire, but only one PCI express slot. Since the proposed video card only uses one slot, I don't need to upgrade my motherboard, right?

Hardware gurus, please offer your wisdom.

It's been my experience that PSU's either work or they don't. I looked up the specs and doesn't look like you have onboard video to test if it's working or not.

Typically (and I use Asus boards) you'll get one long beep, followed by two short beeps if your video isn't working correctly during the boot process. Before you jump ship and replace the video card, take it out, use a can of air and clean everything inside, the slots, etc., and re-seat the card and re-seat all the power plugs and connectors inside. If you have more than one available power plug to use for the video card, try using another one in case that plug went bad. And make sure the monitor's connected, etc. If your video card has more than one VGA/DVI connector, try using the other one to see if one of the output connectors kicked the bucket.

Also, if you've got more than one PC in the house, see if your monitor displays a signal on it. Or if you have an old/spare monitor to try do that and see if you get display on it. It's possible your computer completely survived but the monitor went bad. Which could account for why your PC gives you no error beep codes but you have no display.

As for ATi, I'm not as familiar with them so I can't really help you there. But that ATi card has two cores on a single card, so I would imagine since Crossfire is supported by the chipset the OS/motherboard should treat it as such, even though it's a single card. Someone else here with more knowledge on SLI/Crossfire should be able to give you some info on that but I believe it's chipset dependant and your OS shouldn't matter.