Windows XP Profiles

You can alter the registry key for the second login to point to first profile.

Check this excerpt from a TechRepublic Article: "Two Ways To Better Manage Local Win2K Profiles", it should fall under the same principles in XP.

Redirect a user profile
After reinstalling Windows 2000 on a system with an existing Documents And Settings folder, you'll probably see that a new user profile replaced your old profile. For example, assume you log on as administrator, and in your previous installation, your profile was stored in Documents And Settings\Administrator. You install a new copy of Windows 2000, name the computer MYPC in the second installation, and delete the original. The problem is that your account now uses Documents And Settings\Administrator.MYPC as your profile location. All of your old data still resides in your original profile folder, which houses your desktop, My Documents, and application data.

Figure B

You can redirect Windows 2000 to your old profileby editing the registry. Open the Registry Editor and then open the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList. Under this branch, locate the key that contains your profile settings. The easiest way to identify the correct key is to check the value of ProfileImagePath (see Figure B) in the key and locate the one pointing to your current profile directory. Then, edit the value of ProfileImagePath to point to the old profile path. Log off and log back on. Thisshould restore your original profile.