What do I do when the Blue Screen Of Death pops up everytime I turn on my laptop?

I can’t get to any of my files to back them up before the BSOD turns up and prevents me from doing anything else.

Started happening right after McAfee told me it had deleted about 3 trojans. I think I know which website I got them from, but that really doesn’t help me now.

What can I do to try and salvage my computer?

(It’s a Dell Inspiron running XP. Also, I know very little about computing.)