Imac A1224 wont turn on!

I recently went to visit my Grandfather and he had a Imac A1224, which used to run fine, but since he doesn't really understand how to use it he stopped using it for a very long time, I was the only one using it, but only when I visited him so the computer started to get slower, and some lines appeared in the screen. Then after a while I came back, and the computer didn't turn on at all... (He lives in a very very humid area near the beach, I don't know if this is relevant).

Since I cant turn on the computer, I have no idea of what software its using, but here are the specs that I do know,

Imac 20"/2.4GHZ/1GB/320GB/SD/AP/BT

Model No.: A1224

Thank you!