Xp hangs at logon

[ThunderbirdVII]

I'm having a problem with the logon/password screen on a compaq computer 3.x ghz celeron processor 1.5 Gb memory windows xp pro upgraded from xp home. When the logon screen comes up the cursor does not show/up blink in the password box when you click on one of the three users. Once you click on the user it won't allow you to change to another user. If you type in the password it waits for approximately one minute, then suddenly fills in the password and logs on. I have done a repair install, with a windows cd, uninstalled Norton, checked to make sure OS has all upgrades/patches, made sure the MB bios is latest version available, Googled for an answer etc. I have several years IT experience with a public school system, but have never seen this problem and neither have my colleagues. Usually I would format and start over but the client has lost software cd's for some of the additional software. System seems to be stable otherwise. Has anybody seen this one?

Thanks

[ThePoor]

When at the logon screen, press Ctrl+Alt+Delete twice that will bring up the domain style logon screen try that to see if it works.