CSI: Video Card Damaged

Hello there tom`s hardware people!

Yesterday there was an "interesting" electrical event at my house, and it seems the only victim was my Video Card (AMD Radeon 5850 HD /sob, poor thing was only a year old, service will be held tomorrow at noon, being replaced by a 6870), at the moment im looking for possible culprits of this horrendous crime. Behold, the facts:

During this event, lights did not flicker, but the house second desktop pc, froze completely up and the fridge turned off (connected to a power surge thingy), no other appliances were affected (tv`s, consoles, laptops, etc...)

My computer was connected to a APC 550W UPC (who had helped me in other ocassions)

After the event, the only thing visible in my screen was an assorted rainbow of colors full of artifacts (i think thats what they are called, computer completely frozen)

Upon reboot, no beeps or post messages, electrical current was flowing, fans working (even the one in the gfx), harddrive spinning and all lights were on.

Tested all ram sticks, nothing

Cleaned and reseated the card (had a bit of dust, nothing excessive) nothing

Checked the power supply (red lights, beeps, out of normal stuff), nothing

Checked the harddrive, nothing

Checked the video card again, took away the fan and checked all the electrical work for possible blow outs or deformation of those cylindrical thingies, nothing.

Finally took the video card from the other desktop (low budget card-ish) and tested it, voila! it boots and works.

Now my question is, how can i tell that the culprit was this weird electrical occurence? (atm i cannot test this card someplace else because noone i know has a PSU for it x2 6 pin). Is there something i could observe (physically) that could indicate malfuction? Could there be other causes? such as?

I would like to thank you all in advance for any comments. Help me solve this case!

Sincerely,

ithinkthisfitshere