My (I think '07 or '08) MBP 17" was working just fine. I was watching a few (very) small .avi videos off the internal drive. ...
I think mine just failed last night. It's been running (literally) 24/7 for over four years since I bought it. I was never even aware that there had been an issue, until now. So, I'm basically left with tearing my HD out so I can off-load the data onto another computer. Sucks eggs. But luckily the computer has been little more than an email machine for a few years. But if I were you, I would do a complete HD backup on yours, now, to save that extra step if your machine WERE to fail soon. I can't even boot mine off a system DVD to do anything - which I've posted about here - with no helpful responses yet.
I think I have this same problem with my 17" MBP. But I also can't boot off a CD (OSX disk nor Disk Warrior). The machine just spits the disk back out. Is that because the video card is toast, and the machine won't allow any activity???