PC keeps rebooting when the modem is on

Hi, I've got a friend who's pc keeps rebooting when her modem is on. She tried turning off the modem and powering up the pc and it turns on fine. But it reboots when the modem is on first before the pc.

When she turns on her pc before turning on the modem, it works fine but she can't connect to the internet. Looking through the Control Panel > System > Hardware > Device Manager it doesn't detect any errors with the modem. I haven't encountered this problem before and I was hoping someone could help us. Thanks

when you say it reboots, does it pop up a little screen saying your computer will reboot in 30 seconds or some other number.

if so your problem is that the RPC process is dieing on you... this may be due to some of the nasty viri out there. one comes to mind sasser.....

a temp fix for this is to set the rpc service to restart on failures. this will allow you to get online long enough to do a good virus scan from say symantec or trend micro.