have you created the same username and password on both computer? this may help,

network analysis
Resolution for IPC$, Incorrect password or unknown username problem ... Test and
analysis: some laptops with workgroup network settings and some desktops ...
www.chicagotech.net/analysis.htm

Bob Lin, MS-MVP, MCSE & CNE
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
This posting is provided "AS IS" with no warranties.
Don't send e-mail or reply to me except you need consulting services. Posting on MS newsgroup will benefit all readers and you may get more help.
 I have a laptop that is connected to a school network (domain controlled) and
 my normal home computer. When I connect the 2, I can connect to my home
 computer through the laptop, however I cannot connect to my laptop from the
 home computer... When I try to log onto the laptop from the home computer, it
 won't allow me to do so... What passwords/user names do I need to use or what
 do I need to do without locking myself out of the domain which I have done
 previously?
 HELP!