And he replies, "yup, I had to go into network properties and close out really fast and then go to the address. In order for it to work I have to keep moving my mouse around."

Believe it or not, he's actually describing a symptom I've seen.

He's got a serial-port mouse which shares an IRQ with the COM port that the modem is on. Either that or his USB/PS2 mouse is sharing an IRQ with the ethernet card. (Depending on whether he's connecting via dialup or LAN.)

Troubleshoot his IRQ's.