Apple id query

I have just visited apple apps to download a recent update to garage band when click update the usual box appears the first part normally has my apple id already filled and the second part of the box requires my pass word,but today the apple id that was filled in was not my apple id(the filled in id was superfohn_bananendate@gmail)don't know were this came from but I cannot remove it as my apple id box is greyed out,put my apple password in the box provided just to see if the update would download.All I got was a box saying,This apple id has been disabled for security reasons clic to reset your account.Has anyone any ideas as to what this might be,have not clicked on reset my account in case this is a bug of some sorts.Any help would great.
regards Ray

You (or someone) have installed a hacked application on the machine. A google search of that email address will return multiple results - this is one of the best posts on the subject.

Thanks for the information,after following the leads from your advice I put the update item which was garage band into the trash then went back to the apps update and the 1 update that was there originally had disappeared so am hoping that was the app that was causing my problem.

For others reading this, FYI: don't use an app update link on a 3rd party web site for any app that comes from the Mac App Store. Go directly to the App Store.