XP Home networking; Machine can’t see itself!!

I have two windows XP home PCs and at some point (not sure when), one of them stopped being able to network/share with the other.

After extensive testing, I’ve discovered that the machine can’t even browse itself.

\\192.168.1.55 (PC’s IP)
\\Machine2 (PC’s name)

I get the generic “unable to connect to specified network” crap.

I’ve already tried to rebuild the network using the “Network Wizard” but to no avail.

Any help would be appreciated.

Thanks!
William