Anyway, we had a user who would get the following error in Microsoft Excel 2003 whenever she hit Control-C to copy and paste:
Microsoft Visual Basic
System Error &H80004005 (-2147467259). Unspecified error
I first had her close excel, then I made sure no other excel processes were running in the background. Then I had her open excel again, this did not solve the problem. I then had her reboot, and when her machine came back up the error happened right away when opening excel.
I closed excel, then re-opened it. This time Excel notified me there was a problem with one of her add-ins. It was an add-in for Euro money conversion. She didn't need it so I disabled the add-in and it worked fine.
If you are having the same problem, or know someone else who is, check their add-ins. If you know of a way to fix the add-in itself, let us know in the comments!