The first thing you can do is to do a system restore. Bootup in Safemode.
When you see the first screen (it's black and usually shows the logo of the motherboard manufacturer. This is called the post process) Hold down F8. You should come to a screen that looks like this:
If you see somthing like the following, just click F8, and you should go to the screen above.
You should be promted with the restore guide automatically. If not, go to start and search "system restore".
Restore to a point before this happened.
If the doesn't work. Take a picture of the blue screen. It show an error message that we can use to pinpoint the problem