I've had this happen while trying to compose a email in MS Outlook and a similiar issue while using MS Word.
The last time while trying to enter the email address into the field, all key inputs just ring a bell sound. After this happened, I can't enter any text into the search field in the W7 Start Menu either. Closing MS Outlook and reopening doesn't help. I opened another app and was able to enter text again. Opening MS Outlook again and all was normal again.
Using MS Word on a document, pressing the ENTER key deleted the space between paragraphs and the first character of the next paragraph. That time I just rebooted and it corrected itself.