Somehow I've lost my administration privileges while installing Leopard. The 24" iMac only had a single account and it now is no longer admin. I tried rebooting off the Leopard installation DVD while holding down the "C" key but it boots straight into Leopard. If I try reinstalling from Leopard it asks for my user name and admin password. I also tried booting up holding down the Command and "S" key in an attempt to get into single user but that didn't work ether. Basically I'm locked out of installing new software unless someone knows a fix.