Windows 7 no longer can connect to XP...

I have a network with 6 computers, 2 have windows 7 and 4 have XP.

I rebooted one of my XP's today and now my windows 7 machines can no longer access that XP computer. I had 3 external drives mapped from it and none of them work.

I can access and computer back and forth but both windows 7 machines will not access the one XP anymore, if i try to map a drive it keeps asking me for a password and will not take any that are used.

These computers have been networked for years and nothing has changed on any of them latley, everything was working fine till i rebooted the xp machine.

I have checked every setting on all machines and everything is set right, i can ping all machines back and forth.

I can get to the other 3 XP machines no problem and they are set exactly the same.

Any ideas?

No one has any ideas?

I have checked everything online and everythign i know and all settings are right on both the windows 7 and the xp machines..

I can get to the 7 from the xp but when i try and access the XP from the 7 it asks for login info, which does not work.. But yet i can get to the other XP machines no problem.

I am at a loss right now and it is importaint as this machine has 3 external drives that i need to have access to from the 7 machine..

Any help is appreciated...

Yes i have 6 computers, 2 windows 7 and 4 windows XP - they have all been working fine for years.
All of a sudden yesterday one XP machine cannot be contacted by either windows 7 machines.

It is Windows XP Home
Guest is disabled
and Bill is on all machines and has no password on any of them.

And it is set up exactly like the other 3 XP machines and they work fine, it worked in the morning yesterday then i rebooted and this is what happened, nothing changed at all on the machine before the reboot

I have already tried that and still both windows 7 machines can't access it. The other XP machines can still access it fine.

Every computer can access each other back and forth just not the windows 7 to this one XP.. and like i said it was working for years and nothign changed so this is why i am lost with this... :)

Just so you know i also tried ....
removing all the shares from the xp, deleting the network, reinstalling the network drivers, resharing the xp drives, disableing all antivirus, i have no firewalls, added a new user account and tried that, scanned for viruses...

I can ping the machines no problem but cannot access the xp at all