None of the startup entries are there.Looks like we're spinning our wheels a little.
I have XP Home and Vista,so I'm not too familiar with the Power Users group at all.I do see from this page they are allowed to install and modify programs:
http://www.kellys-korner-xp.com/xp_groups.htm
I'd think creating start-up keys in HKey_Current_User would be allowed,too,but I can't say that with all certainty.
Is there an Admin that could possibly help you set things right,if you ask them for help?
Did you get any prompts from Teatimer when inserting the startup entries?