As the logon hangs before the splash screen, it probably isn't a powerfuse problem.
But I see it in a lot of environments with Citrix.
Things to check:
* roaming profile. Check how big it is. Things as the java cache, files on the desktop, etc. let the profile grow big. Big roaming profiles need a lot of time to download when a user logs on.
* msie branding problem. See
http://support.microsoft.com/kb/941158. The registry key is important and can speed up things.
* printer client mapping and/or drivemapping problem. Check your citrix policies. Try to disable client print mapping or drivemapping and see if the probleem keeps existing. If not, you have a printer driver problem (use universal printer only for client printers) or connection problem to (not existing) drive mappings.