Windows Vista problems - no login screen?

I’ve got windows vista on my dell laptop that I’ve had for about a year. I use it all day for my job and it over heats frequently.

Finally my computer died. I have no log in screen. When I start it up it asks if I want to run the computer in safe mode or normally (I’ve tried all options)—but no matter what you click it just takes you to a blank screen. No log in.
I can move my mouse about.. but its just all black. No wallpaper, no words, no nothing.

so I’m curious… is there even anything I can do about this? Thanks so much in advance. I’d hate to buy a new computer.