All accounts are shown on the "Welcome Screen" & you can only Switch Users if you have "Use Fast User Switching" ticked in "Control Panel" > "User Accounts" , "Change the way users....."
Then you can press Windows+L to switch Users.

I assume you mean by "Account Screen" the Desktop shown when you have Logged on to an account.

Can you use "Turn Off Computer" , "Turn Off" & "Restart" when you have Logged on to an account Desktop . ?
How do you Turn off XP from All Accounts (Welcome) Screen as "Turn Off Computer" isn't normally shown on Welcome Screen. ?
Do you use Power Button to Turn Off.
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If you have Norton 2003 see this info;
http://service1.symantec.com/SUPPORT/nav.nsf/docid/2003020610443906
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You could try running SFC , which checks protected System Files for corruption & if found replaces them from reinstall..XP CD .
If it prompts for XP CD , hold Shift key while inserting XP CD to stop Auto play.
Use Start > Run & type
sfc  /scannow  (space after sfc)

Message Edited by gryjhnhpe on 12-05-2003 10:19 PM

Message Edited by gryjhnhpe on 12-05-2003 10:42 PM