There's a key called "insert" on your keyboard - mine is directly above the "delete" key. Try that.

It happens to me, too. Press the insert key prior to typing. That works for me.

1) The "insert" taste usually toggle between inserting and overwriting. 2) "The Insert key (often abbreviated INS) is a key commonly found on computer keyboards. It is primarily used to switch between the two text-entering modes on a personal computer or word processor. The first is overtype mode, in which the cursor, when typing, overwrites any text that is present on and after its current location. The other is insert mode, where the cursor inserts a character at its current position, forcing all characters past it one position further. On early text-based computing environments and terminals, when the cursor was in overtype mode, it was represented as a block that surrounded the entire letter to be overstruck; when in insert mode, the cursor consisted of the vertical bar that is highly common among modern applications. Overtype mode can also be referred to as overscript mode, and is sometimes erroneously referred to as overstrike mode, which is a typography term. This button is commonly referred to as being the most annoying button on the keyboard, but some would say that's Caps Lock." Source and further information: http://en.wikipedia.org/wiki/Insert_key