Hey Lasereth, I need your knowledge with a rather pathetic problem on my hands...

Unsatisfied with my ATI Radeon 1950 Sli ready video card (I bought last year for 205, blech!), I purchased two Asus Geforce 9600 GT cards for 194 each from a local dealer (less than what I would pay at Tiger Direct after all the taxes and S/H fees), happy to discover with Asus to Asus compatibility, you get a 10% clocking boost! sweet.
Anyways, I know you should uninstall the drivers before pulling out the video card, but, I basically pulled the guts out of my computer and cleaned everything out before I even considered buying new video cards.
So, last night I put the guts back in (never touched the RAM, but everything else was disconnected at one point or another), and pop in the two new cards with the Sli bridge....no signal to the monitor.
As dumb as this question sounds, I'm going to ask it, to heck with it all!
Do I have to take out the memory sticks, wait a minute or two, and pop them back in to get a signal to the monitor? What's the deal there?
Will I have to reconnect the old video card to uninstall the driver, then put the new ones back in? I doubt that should have to happen...since when do video card drivers deny a pc any sort of monitor signal!
Before you have to ask me: yes, PSU is Ultra 600W ATX(above par for two sli cards as far as I know), all connections are in where they need to be, and cables are secure. BIOS gives me one beep upon booting system.
What's the missing puzzle piece? :P
Many thanks.