NVIDIA GeForce 8400GS 256mb Blank Screen

Hey everyone,

So I'm posting this in the Graphic Cards section because after troubleshooting it appears as if the card is my problem. So about a week ago, my computer started lagging really bad, which is usual. The computer is about 7-8 years old so every so about two times a week I restart her to give her a little "boost". She is kept on 24/7 (yes, my computer has a pronoun) besides the random night (VERY random) that I turn her off and give her a break. So when I restarted her, she got as far as the Windows 7 Startup screen, and shut off. Then I booted her back up and got a blank screen. I thought, okay, she just really hates me right now, I'll switch the PSU rocker to off for the night.

So I did, and the next morning, I switched the rocker back to I and tried her, and nothing. So, I took my graphics card and wireless card out and tried using the onboard, nothing. Tried unplugging my HDD, nothing. Tried reseating the RAM, nothing. Reseated my CPU fan, nothing. Opened up and reseated the PSU, nothing. Reseated EVERY plug in the computer, nothing. So I then processed to clear the BIOS by removing the battery for two hours. YES, it worked (by this time my graphics card was back in). It got as far as the Windows login screen, and froze. So I powered her down using the rocker switch. Tried to turn her on and off a few times, nothing. So at this point I unplugged the HDD and tried to get into the BIOS to update it. After a lengthy process of getting the computer to recognize the jump drive in the EzFlash2 utility, I got it updated. However, as soon as I plugged the HDD back in, it stopped again. So from there I proceeded to unplug it again, and the computer wouldn't boot. So I pulled the CMOS battery out and left it out for the night.

The next morning I put it back in, tried to turn her back on (with the HDD unplugged) and I got nothing. So at this point I took the graphic card back out, and tried, and got nothing. Left her for another night because I was cranky and didn't wanna deal with it.

SO now we reach last night, at about 3am, I reset the BIOS by moving the jumper (with NO GRAPHIC CARD). I plugged the HDD back in, everything in besides the graphic card. The computer turned on, went and logged in to Windows, and sat at the desktop for a good 15 minutes until I shut her down. After that I reseated the graphic card, and it wouldn't turn on. So I have this strong feeling something is wrong with my graphic card but I don't know what.

I have the NVIDIA GeForce 8400GS 256mb. The fan on it is running. I have tried both the VGA and DVI ports, nothing. Help!