why does it do this... did i some how press a key combo that makes this happen.

Please give more details, is it a simple delete? or actually the text was replaced by space? If it's the latter case, probably you switched to overwrite mode, press "Insert" to go back to insert mode.

Ya I pressed the Insert button near the Page-up, Home Buttons,
That can really be annoying if you do it by accident.
Thank though