win XP blue screen at start-up

I have a AMD 2200 XP, Win XP(Home Ed SP1), 256k ram, 64m Video, DSL Cable modem thru router.
Problem: Sometimes when starting up,after the icons show on the desktop,it shows a blue screen with a page full of white lettering, but not long enough to see what it says.(Tried the pause key and even print key.) After this screen it restarts.
What’s on the blue screen, or what can i do to fix this problem?