Widescreen Wallpapers

Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_gdr.101209-1647)
Language: English (Regional Setting: English)
System Manufacturer: Dell Inc
System Model: XPS 630i
BIOS: Phoenix - AwardBIOS v6.00PG
Processor: Intel(R) Core(TM)2 Duo CPU E8300 @ 2.83GHz (2 CPUs)
Memory: 3070MB RAM
Page File: 521MB used, 4433MB available
Windows Dir: C:\WINDOWS
DirectX Version: DirectX 9.0c (4.09.0000.0904)
DX Setup Parameters: Not found
DxDiag Version: 5.03.2600.5512 32bit Unicode
Display Devices
—————
Card name: NVIDIA GeForce 8800 GT
Manufacturer: NVIDIA
Chip type: GeForce 8800 GT
DAC type: Integrated RAMDAC
Device Key: Enum\PCI\VEN_10DE&DEV_0611&SUBSYS_053C10DE&REV_A2
Display Memory: 512.0 MB
Current Mode: 1440 x 900 (32 bit) (60Hz)
Monitor: Plug and Play Monitor
Monitor Max Res: 1600,1200
Driver Name: nv4_disp.dll
Driver Version: 6.14.0012.7533 (English)
DDI Version: 9 (or higher)

I upgraded from the Nvidia Geforce 8800 GT to an EVGA Geforce GTX 560 and as I powered on the first time got an error screen that read irql not less or equal. I was able to go into safe mode and then got another error that read bad pool caller. I shut my pc down and took the 560 out and put my old video card back in it gave the same errors and shut it down again. Then I restarted and now all I get is a black screen, no windows logo, nothing. The pc is powering on, the fans are working, all the lights are on just nothing on the screen. I read that it might be a ram problem so I took the ram out and put back in but that didn’t help. What could the problem be?
Edit- I can’t get to Bios at all now, just a black screen and it seems that my pc is working very hard, like the fans are on overdrive. It’s bizarre-
Edit- inside the case says 750 is max output power

Ok so i recently bought RIFT for my PC and ive been playing it on low graphics because the program said that’s what recommended… i went to can you run it . com and checked if my requirements matched up to what the recommended requirements were on the box since i bought the digital version. and it says my computer should be able to run it and that i might be able to run it well so idk what the issue is with the game im quite tired of all these issues with the graphics and sometimes my comp freezes during game play and everything i used to play Lotro on high to very high settings with out having any issues and that game was much more beautiful than this one!
ok heres my system…

windows vista premium 64 bit
AMD Athlon 64 X2 duel core processor 3800+ 2.0
2046 MB of ram
512 MB GeForce 6600 (up to date drivers)
1440 x 900 res but since it runs to choppy i usually bring it down to like 1240x 720
and i have a great internet connection

so my question is how can i run Rift better and what should i do to get there… thanks