Ugh! problems with my monitor

So, I came home from a weekend out of town to a striped computer screen! Multicolored, thinly striped screen. And now, if I turn it off and turn it back on it slowly gets darker from the corners in. So to all the computer smarty pants out there, is it a virus, the video card, or the monitor? How expensive is this to fix?

I'm not a computer 'smarty pants' but once our computer monitor did that, when we took it they said that something was poured over it -hmmm who might that be- so the guy cleaned it up for us, but it still had an orange glow to the side, because we didn't take it early enough so we had to get a new one.

Hmm well once, when I went away for the weekend, my roommate at school did have an amazingly explosive can of soda that covered all of our walls, but that was almost a year ago.