Hello and welcome to JustAnswer~! My name is Travis and I would like to assist you with your question.
You can try to do a repair on your excel installation. If you have the cd, just put it in and it should open and ask you if you want to remove, repair or reinstall. I would try a repair first. You could also try deleting the file below to see if it's something that was saved in your template.
Click start, search on windows 7 and type %userprofile%\AppData\Roaming\Microsoft\Templates and delete all the excel template files. xlt or xltx files Make a backup if you are unsure if you need them or not.