Yes you can ask it to restore its configuration to an earlier 'saved' restore point. Restore points are saved before Microsoft security upgrades.
You should be able to do a system restore, if that doesnt work simply reinstall the excel from your Microsoft Office.
normally it is in administratotr documents(my documents)
Volume Shadow Copy service or System Restore service
You will need to restore from backups or reinstall the software.
Microsoft, depending on the system, offers many types of back up software. I know for my computer I got a restore disk that had all programs my computer originally came with. You can back up many files to discs or even on the computer, such as restore. Extra hard drives are also available for purchase.
I had the same problem either, and no matter what i tried to do i couldn't fix it..... u have to use system restore sorry
Backing up and restoring information requires some sort of system. There are various programs available that can perform backups to Exchange computers. Microsoft and eHow provide guides on how to perform a backup and a restore.
check the article How do I restore security settings to a known working state? from microsoft
Create a restore point.
System Restore is a system utility in Microsoft Windows which allows the user to roll their computer's state back to those of a certain point in time, which can be used to recover from system malfunctions or other problems.
Volume Shadow Copy