Excel 2007 : Paste special doesn't work anymore

Hi,

Since yesterday, I'm not able to paste properly anymore in Excel.
If I enter a formula in a cell, copy this and paste it in another cell (CTRL+V), it only pasts the value, not the formula itself.
If I copy the formula and click Paste Special, I'm only given the option to paste as Text or Unicode text.

If I copy the contents of a cell (CTRL + C) and try to paste it in multiple selected cells at once, using CTRL + V, I get the error "data on the clipboard is not same size and shape as the selected area, do you want to paste it anyway"
If I then say Yes, it only pastes the content in the 1st selected cell, the other selected cells it leaves empty.

What does work is copying a formula by pulling it down, using the cross at the bottom right of the cell.

I'm using Office 2007 on a Windows XP computer. I have already re-installed Office, but this hasn't helped. I have opened the same document on a different computer, without any difficulties.

Anyone any suggestion on how I can fix this?

For those interested: this problem is solved!
It was a weird bug in Acrobat Reader. I now removed Acrobat Reader from my PC and Excel works perferctly fine again.