iMac Cannot Log In

The password that i made for my administrator account doesnt work for some reason and i wrote it down i have tried typing it wrong and adding numbers and uppcase etc..i wanted to reset the password by holding "C" as the computer started and now it takes me to a log in screen where it ask for my password and i cannot log in because i dont have the password or the master password..also there are no other accounts and when i try holding the "C" button down at the beggining it just goes straight to the log in screen so what do i do please reply..

The C key is for starting up from the optical drive if you have the restore disk or OS X install disk in there

louishen said:

The C key is for starting up from the optical drive if you have the restore disk or OS X install disk in there

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yes i try to load it from the disc but it doesnt do anything and i read that its supposed to goto a menu to let me reset the password

what sort of start up disk is it?

in os x can you select that disk in system preferences > startup disk

install disc one and ive tried 2 and none seem to work