Vista - XP computer not showing up in LAN

I am running Windows 7 Ultimate 64-bit on my laptop and I am trying to map to a network drive on my XP desktop. Until about a week ago I was able to do this without any issues.

All of the sudden my laptop was no longer able to connect to the network share. I am not even able to see the computer within my network. I have worked on this for days and I absolutely have no clue what happened. Both computer are on the same workgroup. I have verified the spelling was correct and reconfigured and rebooted the machines several times to no avail. I am able to ping the XP machine as well as RDP locally to it without an issue. Windows firewall on both machines is turned off.

I have also connected my Asus EEEpc to the wireless network and was able to map the network drive without a problem. This would negate any problems on the XP desktop, router etc. I am pretty sire at this point that I am dealing strictly with a problem on Windows 7.

All netword settings are enabled on the Windows 7 machine. Network locator, file/printer sharing, public folders, etc. I have also tried setting both machine's IPs statically and remotely with no success.

After reading a TON of message boards someone had suggested making a change to the registry (currentcontrolset/control/lsa and setting the lmcompatibility value to 1 (from 3). Momentarily I was able once again to see the desktop on the network, although I couldn't see any shared drives. Once I rebooted I was no longer able to see the computer on the network.

I am almost positive that no updates to Windows were installed. All of my AV software has been turned off. No settings have changed in my router, and I can gurantee that my firewall is not blocking anything.

Please, someone give me a little guidance. I am about to lose my mind.

Thank you so much!