Yosemite won't install after recovery due to not accepting password

[Milton W]

Hello out there. I'm a new Mac desktop user. I have a mid 2009. I erased contents on hard drive due to an anti-virus program that slowed the computer to a crawl. Now I can't reinstall because it doesn't accept my password. I even tried credentials from a current account that i use on my iPad. I've tried all the most popular suggestions with no positive outcome. any new suggestions would be appreciated

 

[Milton W]

I tried my son's credentials and it downloaded. solved

 

[oldscribe]

Hi,

Good to hear.