Good afternoon.

I have a user who uses excel quite a bit for their job. This has been going
on for a while, and has just been brought to my attention. The user has
reported that when they work in excel on workbooks that contain 30+ sheets in
them. Some of them require the same formula on each of them. They have been
able in the past to copy that, and then paste it to all of sheets. Now they
only get about 6-10 pastes done after a copy before the program blows up.
They lose the function to ctrl+c, and ctrl+v, and then have to manually go to
copy, and paste each time they want to paste that cell into the next sheet.
Some times they lose the ability to copy, and paste with their mouse buttons.
They have no physical issues with their PC, and no other issues with any
other software on their system.

My question is:

Has anyone run into this issue before, and if so how does one fix it? The
way it was put to me is that, that is the only thing that is messing up with
the application. I would really hate to do a repair, and possible reinstall
of office just to find out that it didn't fix the issue. I've searched
online (google searches) on this, and have turned up nothing. If anyone has
an incite as to what might be causing this, or if they have run into and know
a fix please respond.