I had to clean out my PS2 twice, once it worked fine afterwards...the other time it died completely and won't even power up.
On the plus side, I'm batting .500.
If you've already opened it up, you won't be able to send it in to Sony, so you might as well take Pablo's recommendation and get a qtip and clean the laser.
When mine died I figured it more cost effective to just switch to PC games, which is what I've done and I have no regrets about that. The graphics are actually better, to be honest. You don't need the newest and best computer, as long as you have a good video card you'll be fine.
Good luck with it, just be careful.