Screen kept staying black, now windows won't load

hi everyone!

my dell laptop itself had been running fine, but i started using a mouse (which had formerly been my brother's), and then my screen just wouldn't turn on. i cpuld hear the sound going off and on, and the computer itself seems to be logging on, but the screen stays dark. if i powered up and down many many times, and plugged and unplugged the mouse, sometimes the computer would log on.

so the last time the computer worked, i restored it to a previous point, to a time before i had even started using the new mouse. and... i think i REALLY messed up my computer.

because now, the screen doesn't work most of the time, but when it does, it asks me if i want to log on normally, or in safe mode or in the last known settings that worked. i've tried running all of them, but it now tells me "windows couldn't start because the following file is misisng or corrupt: \WINDOWS\SYSTEM32\CONFIG\SYSTEM. that's bad, isn't it? it says i should use the original set-up CD-Rom to restore, but i don't have that.

help, please!

 

The black screen might be a worry. Do you see the Dell splash screen at startup, then it goes black or is it black from the very start?

Sounds like it is black from startup.

Do you have an external monitor you can try connecting to it?

Matt