can't download system updates

[signinteach]

when I try to down load system updates, I get a message that says I need to have permission to do this activity.....I'm the only person using my mac OS10.3.9

Some how it's not recognizing my password.

 

[Satcomer]

Have you read HOWTO] Reset User Password via single user mode? Have you read the Apple article Mac OS X: Changing or resetting an account password?