Could overuse of particle effects have destroyed my video card?

I was testing a game level using some explosions and everything ran smoothly but suddenly the display turned weird psychodelic colors and locked up, no errors, no nothing. I had to restart the computer. Now it can't handle Unity at all,everything turns weird colors and then locks up. After multiple restarts of my machine, it even screws up when I use the internet now. Have I melted my video card? I'm using an Nvidia 8800 GT in my machine and it no longer works properly according to the device manager.

I also installed the latest updates for the video card as well and the problem still makes Unity basically unusable, my internet and other programs barely usable without the screen getting choppy and funky.

Your graphics card is malfunctioning, and you'll probably need a new one. It's almost physically impossible for software to destroy hardware, so don't blame Unity or anything else for a hardware malfunction. This isn't even Unity-related, really.

Although a well designed and cooled videocard shouldn't overheat (and normally termal protection would kick in before it happens), it is possible to kill a card from high load if fan is dead or airflow is really terrible. This is a fault of your videocard not Unity as your card should be able to handle full load without problems.