Windows 7 ask's "enter network password" when accessing Window XP Machine

I've got same problem with logging into windows xp pro. from the beginning everything was O.K. and then out of nowhere.. i couldn't access my data on remote computer. in my case the main problem lied in wrong date. (i forgot to set up date after replacing battery in my motherboard) and I couldnt log in even using correct data : login and password. after adjusting date everything is O.K. hope it will help you.

I also had the same configuration...Windows 7 Pro on wireless and XP on wired and the same problem.  I could not see my XP machine from Win7.  Turned off my wireless and switched over to wired on my Win 7 machine.  I then could see my XP machine.  However when I tried to access the shared folders on the XP machine I got the "Enter Network Password" popup.  I have the same account and passwords on both machines.  I tried everything that was suggested in the forums I looked at but nothing worked.  Finally on the XP machine I went into the Local Security Policy Settings" section to see if there were settings that pertained to this problem.  Start>Settings>Control Panel>Administrative Tools>Local Security Policy.  I right clicked on Network Access: Sharing and security model for local accounts then selected Properties.  I selected Classic - local users authenticate as themselves.  Then clicked OK and closed all windows.  Rebooted the XP machine.  Then tried again from Win 7.  I got the shared folders on XP without any user name or password.  I am still having a problem with the wireless access though so I have to work on that next.

One suggestion I read was to check that the drivers for your wireless and LAN devices are from the actual vendors.  You can check that in the Hardware Manager on Win 7.

This problem happened to me this week 7/20/11 and no solutions I could find anywhere on the internet worked including network setup, workgroup, credentials, checking the date, reinstall XP, virus scan, sharing settings, creating duplicate users, matching user passwords, ...etc.

It turns out I have AT&T U-verse and the router was going bad.  Once they replaced the router it didn't ask for ID and PW any more.

My suggestion...after hours of trouble shooting with no solution...replace your router. Hope this helps.

Hmm, I'm having the same problem right now, and what's boggled my mind this whole time, is that it only happens SOMETIMES. Most of the time I've never had a problem accessing the XP computer and files. Very intermittent. Reading your post...I in fact have AT&T Uverse and its router. Will look into this next.

Well, it seems like my router is indeed most likely the issue. I turned off the router, unplugged and replugged all the cables back in, and restarted all machines. Worked fine after that. So something's telling me that there may be something going on in my router that is starting to fail. Hope this helps someone.