You're experiencing a blue screen of death. What you could do is determine the actual error code you're receiving. While booting up your computer try pressing (and holding) F8 which will bring you to a menu. Select Safe mode and check first if you can boot from there.

If successful you can access the event viewer which contains the error code. To do that, click on the start orb then type event viewer in the search box then press enter. I'm not quite sure but I think that that there should be a tree (+) beside the word critical. Click that and take note of the error code/s and post back here.

Formatting is the last option especially if you have data that you want saved. Do you have a recovery disc or installation DVD of your Vista Home Premium? If so, try the various repair options namely the startup repair option. A guide can be found here. This is tailored to your operating system.

It's supposed to be somewhere on the DVD packaging. If it's not there and you're unable to read it from the PC, try calling your manufacturer about it.