There is no such thing as a "USB video card"
if it didn't work with neither a different graphics card or monitor, it could be the cpu fried, or psu fried, or mobo fried, or memory fried, or pretty much anything.
try taking out the mobo battery and wait about an hour then put it back in. that'll reset the CMOS and make it work again if you're lucky
You're looking for something like this :