lost myself as an admin in windows 7!

Hi

I am using windows 7. I have two users as adminstrator on this pc, myself and our it manager

I changed the Network ID in system properties dialog from 'This computer is part of business....' to 'This is home computer' and when I restarted my laptop, I did not have my admin icon anymore. I am now logged in with our it manager login details. 

Can I reactivate my account?

Best Regards

AustinCann