could be the network card or driver, start into VGA mode and see if you can spot anything in there...(asuming it lets you in!!) if you can get in, try also doing a search for a file called scam32.exe hope you dont find it!! thats a virus whit symptoms of hanging on startup etc....
good luck! Jay~
"I have to think of a funny footer to
put in here!!!???"
~KeyTech