iMac lamp screen problem

I got iMac lamp (G4 700) as a gift....after years od looking for it (simply love the design)) wanted to make a media station in my living room....It was working fine on the first day...till I moved it to the other desk....since than it seems to work fine but screens does not respond in a normal way....just showing lines and bleached out stains and white screen with black stripes .... any tips ???

 

tought so...but, it was working just fine.....and without any specific reason on the next startup LCD didn't respond :S ...