I'm trying to connect to my friend's computer over a LAN. He has recently got a virus (or a lot of spyware/adware build up). When he starts up his computer, the OS doesn't completely start up. All you get is the desktop background. He's able to open the task manager and use start task to open AIM, and thats about it.
I've tried connecting to his computer using DOS (net use) I was able to connect, but that is about as far as I got. I have his username and password information, I was told that I was connected.
Is this on the right step to attempting to access his computer to extract important files? Once those important files are off his computer, I can help him out and reformat everything (and set him up so he never gets that nasty spyware again).
Thanks for your help.. if you have any other suggestions on going about this problem, let me know. Thank you,

Why not just boot his PC with a floppy or bootable-CD?

You can also try to boot in safe mode. Maybe some of the drivers are corrupted and cannot be successfully loaded.