HP Z620 - catastrophe while trying to install video card - need help recovering

[Nigel_Gregson]

Hi I've been trying to install two nVidia NVS 310 graphics card on the two PCI-e slots of my z620 running Windows 7. I had managed to get windows recognise the two cards and install the drivers. I was also able to display the four screens properly, but it was laggy and hanging upon reboots. So I tried to swap the two cards around. 

And then disaster struck. Now PC wont output power to any screen. I dont even get to see the HP logo and access the BIOS. The power lights turn on for a little bit and then the computer auto switches itself off.

I've tried every permutation possible to restore the hardware to the original state : Used just one card, Swapped the cards back to original slots, replaced them with my old working card, but no luck. The PC simply wouldnt turn on. I fear I might have damaged something physical that I dont know about and so am posting here in desperation.

Would appreciate any help or ideas on how get my PC back to a working state

[Dennis Handly]

This is the wrong company for printers and PC products. You need to register in the HP Inc. Support Forum:
http://h30434.www3.hp.com/