Why won't my screen turn back on, after going crazy... ??

I have a refurb ibook g3/g4 ?? worked great first two weeks.. besides short battery life. Sat it on table and noticed the screen had lines going across it.. going crazy.. when i went to touch it .. the lines went mostly away.. and then froze up.. I turned it off by pressing power button.. and turned back on.. and then black screen.. I waited a couple days.. tried it again.. and tried the safety reboot cntrl/cmd/power after doing that twice.. it booted up.. the screen started up.. and worked great for about 3 hours.. and then screen went crazy again froze and then shut off .. black screen.. I'm about to scream.. I can not figure out what to do.. and I feel like I just threw alot of money away..Please help????