Weird - can not delete columns but can delete rows

[Tony Pony]

Something weird happened after I used a software to clean up trojans in my PC yesterday. Not sure if they are related, but now I can not delete columns in my EXCEL - the selections both on the right-click menu and the standard menu are gray.

I have not any VB work on the PC, nor have I messed with the protection function. Nothing extraordinary and I can not delete columns even on a new blank file.... However, I can delete rows!!??

Can anyone please help? Thanks a lot!