I don't know if this works, but most likely it will, since XP is
one of the most insecure OS around. 
Start > Control Panel > Administrative Tools > Computer
Management
On the left hand side, click on the + sign to expand Local Users
and Groups.
Click on Groups.
Double click on Administrators on the right hand side.
Click on Add when a new window pops up.
Add in your username. Then click on Check Names.
Click OK all the way, restart PC.
Go to Start > Control Panel > User Accounts and see if your
username is under Administrator group.
Don't tell SP, or I mati liao... 
