Try login as default admin account and check. To enable it, Open command prompt as admin and fire the command,
net user administrator /active:yes
Logoff and login as default admin, start the install. Once done, logoff and login as ur accnt, fire the below command to deactivate admin,
net user administrator /active:no
BTW, are u performing a clean install or upgrade? Have u removed prev version of office if any?
Is the new image you doenloaded from M$? Did you extract the exe or just running it?