White screen after I log onto my Studio laptop?

I own a Dell Studio 17 (1749). OS; Windows 7. It's a little over 2 years old, expired warranty.

First, my computer froze, and I restarted it. The start up was completely fine, up until I typed in my password. It took a while for it to log me in, and once it did, all that showed was a blank white screen. I tested whether or not it was the lighting, but it wasn't.

So, I restarted my laptop again, logged in, just to find the same results. I tried logging onto another user on my laptop, and the screen just turned grey.

I don't really understand why this is happening. But if you can help me out, I would greatly appreciate it, because as of that, I'm not able to see anything on my screen after I log in to my user.

Btw, I didn't create a backup disk because it took so long, and now I regret it because some people recommended to do a restart that completely wipe out all my data. There are programs that took me years to find, and pictures that cannot be replaced.

Thanks in advance!

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Also, my computer keeps freezing after 3 hours of usage. It's like that all the time. And I always end up having to reboot it. Is it possible to also help me out with that too?