VBA editor auto changes "." to "'#" as you type ... not just after pressing <enter>?

When typing in a decimal value after entering "." if you wait a fraction of a second it replaces it with a "#", infact it appears that the auto complete function is running all the time, rather than when you press "enter". so single " are made double before you can type any text ?

I have openned the same file on another PC and it does not behave like this, it is normal in that when you press enter it does the double" stuff etc.

I have compared the Tools Options settings and they appear the same?

Clearly I have probably mistakenly set some setting somewhere, but for the life of me I can't seem to see where or how!

Short of a re-install I'm not sure what else I can do, so your help is muich appreciated.

thanks, Richard