.....Giving admin privileges to the other users temporarily, then while in the other user's account, open the "Network Connections" icon, RIGHT click on the "Local Area Connection" icon, choose "Enable". Then check to make sure the other user has an internet connection. Follow this same procedure for all other users. When you're sure you've got all users connect, then change their user permissions back to "limited users".
In regards to pressing the "Windows key + L", the computer is behaving as designed. Pressing that key combination is the "Lock" option in Windows XP. It locks the key and will only allows an administrator or the logged in user to log back in with their password. If you don't have a password, leave it blank and click on OK. If you HAD a password, your password would be required to access the compute again.
In regards to "Switch Users", have you created the correct settings in "Control Panel/User Accounts/Change the Way Users Log On and Off" ? Personally, I'm not a fan of "fast user switching" because there are a number of program, including Microsoft programs that don't function well using it. Instead, I prefer performing a full "log off". It only takes a few seconds longer but it's much more secure...that is, if you have a password.
Hope this helps.
Grif
Since I've switched from dialup to cable, accounts other than mine (administrator) have no internet access. When I log into another account, the connection is disabled and cannot be enabled. Also, I cannot switch users from my account. When I click "Switch Users" nothing happens, and when I hit the Windows key and L, I get a box asking for my password - and I have never had one. Do I have to make all other accounts administrator accounts, to enable internet connections for these accounts?

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