The subject behavior occurs because installing Microsoft .NET Framework 1.1 adds a hidden local account named ASPNET, which Windows treats as an additional user.

To workaround this behavior:

1. Press you user name on the Welcome screen to log onto Windows.

2. Copy / Paste the following to an ASPNET.reg file:

REGEDIT4

\[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserList\]
"ASPNET"=dword:00000000

3. Merge the ASPNET.reg file with your registry, or double click the ASPNET.reg file, or run regedit /s ASPNET.reg.

4. When you Restart windows XP, your desktop appears without any intervention.