mac plus hardware problems

Hi, I just recently got a Mac plus from a good friend and decided to

see if it still worked. I turned it on and, after a long wait, showed

the floppy disk icon. I put in the startup disk and the infamous bomb

error popped up. I can't remember what it said but I remember clicking

restart instead of continue. Nothing happened and it kept reading the

disk and popping it out. The screen then turned black, so I hastily

turned it off. Now whenever I turn it on, the screen is always black,

unless I hit the side hard. Even then, I only get a brief second of

the screen. Any suggestions?