Laptop screen is black. PLEASE help!

Hey,
My laptop screen was working perfectly well for a long time, but then my charger started acting up, and wouldn't charge unless pushed right in. Dad said it might be a lose wire, so I undid all of the screws, but being not so skilled in computers that way, I didn't want to break it by trying to pull the bottom off, and left it (and put all screws back in) xD so anyway I started up my laptop, and the screen wouldnt turn on. I tried every day for about a week to turn it on, but to no avail. So I left it for about a week, and then I turned it on, held down the function key and pressed all the buttons and whacked the side of it gently, and the screen turned on! I used the laptop foor a few hours, had to do some work, and when I got back my laptop had gone into hibernation, so I turned it on, and the screen went black again. >.< I have left it and I've started it up normally twice since, after holding down the function key and f5, But every time it I turn it off, leave it, and turn it on again, the screen is black again >.< it's getting a wee bit annoying lol. .

I've looked up help from other users, but none of it worked permanently. I might have a loose wire in the charging area, and I can't even turn it on with only ac and no battery. I don't have a clue how to fix it.

Please help me!
Thanks in advance =]

Toshiba Satillite A100 series
2.5 gb Ram
1.8 ghz dual core Cpu
256 mb dedicated Video
120gb hard drive
Windows 7 Ultimate
Internet explorer 8