We have a network consisting of 1 Win2003 SBS server, 6 Win98 PCs, 2 WinXP PCs & 1 WinXP laptop. After a period of time when 1 of the WinXP PCs is idle (not sure exactly how long, but definitely more than 15 min.), it can not longer access any data or programs via the network shares on the Win2003 server. The WinXP PC can ping the server & vice versa. The WinXP PC can see the server in Entire Network and vice versa. The server can browse the PC, however, the PC cannot browse the server at all. It asks the user to enter their username & password. We enter this info & a message comes back saying it is not valid. We use the exact same user name & password that we are using to login to the domain upon PC boot. This whole issue goes away if we reboot the PC. Upon reboot, the user can login to the domain with no problem and perform all network functions without a hitch. Until the PC is idle for too long again. And, it isn't consistently happening. Some days it occurs and some days it doesn't. However, if we leave the PC on overnight, it is guaranteed to happen when we arrive in the morning. I checked the Power Management settings to disable hibernation and set the Power Scheme to always on and all other options below it are set to Never. Any suggestions? She had this same PC when they had a Win2K server and never had this issue. We just installed the new server at the beginning of September. Also, this is the only PC on the network that is having this problem. Thanks for reading this and offering suggestions.