Upgraded Video Card, CPU won't POST or Boot

[Yoshistr]

I have a DELL GX280 desktop and decided to upgrade the video card on it, I put in a ASUS EAH3450 (512MB) graphics card in the AGP slot (black color) on the motherboard, when I did this and had my computer on it asked to install the drivers for it, I put the CD in and it installed 2 of the 3 drivers (missing audio driver on the CD that came with the card). Everything seemed fine, the video was displaying through the new graphics card while the old graphics card was still installed (original card is integrated into the mother board but I never disabled it).

After trying it out and finding that I like it I decided to reboot the machine, however on reboot it started having problems, the fans went on and the power button turned a steady yellow (instead of green) and I waited but no graphics appeared and the fan on the mobo continued to get louder until it maxed out. After checking the LED lights on the back I noticed none of them turned on when I turn the machine on, indicating the cpu failed to post, checking the mobo I made sure all the capacitors where not blown or leaking however noticed a steady yellow LED on the mobo next to the label "AUX PWR" indicating a lack of power for the new graphics card.

Now I just want to use the old card but I can't even get the machine to post with the new card removed, I tried to reset the BIOS settings by removing the CMOS battery, I tried to switch out the RAM, removing sticks to check if it was the memory that was bad but now I am confused on what to do at this point.

Any advice would be appreciated to get the machine back up and running, basically I want to use the old graphics card but the drivers for the new one are installed however I don't think the BIOS knows which one to load.

I am not that good with computer hardware so please explain.

My specs:
2x 2GB RAM = 4GB RAM
2.8GHz Intel 4 Pentium
128MB 910GL Graphics Card (Original)
512MB ASUS EAH3450 Graphics Card (New - AGP Slot)
210W PSU

 

[A Cheese Danish]

When you start the computer, press F8, and select Safe Mode with Networking.
It only loads basic drivers, so you can use either card.
Select Start > right click My Computer > select Properties > Select Hardware tab > select Device Manager.
Inside Device Manager, expand Display Adapters. Right click the one(s) you want to uninstall, agree to any
error messages you get, then restart the computer. It should boot up after and install the device drivers.

 

[Yoshistr]

The problem is the computer won't even boot up, the fans start spinning and keeps getting louder but how can I get to safe mode when the computer won't even load the BIOS or POST? Usually the green diag lights in the back come on before it reads the BIOS then gives the option for safe mode.

 

[StrangleHold]

Unplug it and press and hold the power button in for a few seconds a couple of times. Plug it back up and see if it boots.

 

[MyDixieWrecked]

210W PSU

I'd be willing to bet you maxed out the only available rail on that PSU and effectively killed it. That PSU was lucky to survive one video card, let alone two. Test with a new PSU. Cheers.