How do I stop word & excel 2007 from mysteriously copying and pasting parts of the document and pasting over other sections of the document randomly while I am composing the document. I use the mouse like an eraser, not pressing L or R buttons to make some of it go away. This is also happening in Excel. I am not doing any copy Paste functions. It is happening anytime I am using Word saved documents that I am updating. It is making it almost impossible to use word or excel because it happens every time I am in a document.