Excel 2007 misbehaving

My excel 2007 has started misbehaving. A save as window will pop up on its own & when I choose to save it pops right back up. If I choose to cancel, it cancels & pops right back up. When I click escape it goes away. Whats up? Other oddities are occurring on my dell notebook since I have been helping my brother with his dell notebook he just got off of ebay. I remotely access his computer using teamviewer.com. We activated his office 2013 on his machine but he is getting some strange messages like "picture is too large .... it will be truncated". I have found responses on this message with google but all comments relate to earlier versions & I am unable to get his message to stop. If we click ok twice we can go on & paste. Is my machine getting corrupted by his? Help!
 
I would try to do a repair. I believe this can be done through the help menu in an Office app. Otherwise, try a repair, through the Programs control panel (or add remove programs if this is xp).
 
Back