D620 - Invalid Configuration Information - Urgent Help Needed

Background: 2 days ago i opened back of my laptop to look for the DIMM B option. I fiddled with the side jacks as i thought it would lift. I closed it. Next morning, i noticed that the video driver had uninstalled. So i  went to dell site and downloaded the right adapter which was nvidia quadro ...something. after installing, the laptop gave the right resolution. I did a reboot and from that moment onward the latop wouldnt start at all.

Before i opened my laptop i had also installed a driver for my video camera, it was a logitec webcam but i think my webcam is busted so it kept giving harware faliur. not sure if this is related.

anyways, since then I tired different things, removed the batter, did reset on that, took out DIMM A and put it back, even took out the cmos battery..

A few times i was able to get the setup menu and sometimes it wouldnt budge and all lights would just flash... a numer of different things happened...i evem did factory default settings in bios when i could. It mostly frooze most of the times.  The only message that consistently comes is the following when it does start

Invalid Configuration Information - Please run Setup Again.

Then it gives me the option to continue, or f2 for setup utility or f5 for onboard diagnostics. Here is what happens with each of the options.

When i continue, sometimes it freezed during windows startup and a couple times it started the windows and gave me blue screen, and a couple times give me memory issue and said system would reboot and the cycle continued.

f2 for setup. SOmetimes it freezes in the middle and sometimes it freeezed when i exit

f5 diagnostics. sometimes freezes. once it said all was ok and frooze when i hit the reboot key.

Here is what i have done. I bought new ram 2 x 1 gig, and replaced it, tried on A only abd  B only and then both A and B.  nothing major happened.

1 thing to note is that i took the cmos battery out for 30 sec. After that i kept on getting Date/Clock not set. After the initial booting. This was wierd because most of the time it never booted but this time it consistently booted and then gave that error. I reopened the laptop and took the cmos battery out for 30 seconds and now that message has gone and i am back to status quo which is

after initial booting it goes to the Invalid Configuration Information - Please run Setup Again

and sometimes it just doent even start.

Please help.

Thanks

Just rememeberd. A few times in the begining the laptop would start  with lines on the screen.. mostly on the top half.....