-restart computer
-hold down F8 key when you get past the BIOS screen (the screen that flashes what ever brand of computer you have before it starts)
-this will take you to a black and white screen; use the aarow keys to highlight and then enter to select the option that says "safe mode with networking"
- wait for it to start up and once it has close any windows that pop up about restoring to a previous point in time. Let it stay on, or surf the web or something.
If it does not crash in safe mode, then it is likely an application you installed (either one you wanted or a virus) telling us this will help narrow down the issue.