Cannot start excel
 

Every 2 or 3 days as I try to start Excel I get a READY TO INSTALL message
and then it blocks and I am asked to insert the original Installation Disk.
And then it works again...after reading the disk.

Thsi evening as I tried to open same thing plus e message stating that
SKU112.cad was missing.

Again I insert the original Office Standard disk and it works.

By the way it has no bearing if I try to start directly or from a shortcut

Thank you for your help