Can't login to admin.

I am currently trying to instal silverlight again to watch netflix. I go to install and it asks for admin login. I kept getting the error my name or password are invalid and reset my password using the mac os disk. I return to get the error again so it must be the name. I checked my account info and my account name/ homefolder name and just can't login. I try to change my name in the system preferences but when it asks for the admin login to do so. I really don't know what to do now. Any suggestons?

Thanks,

Austin