[users] How to disable auto operations

[Peter Billingham]

I am using a recently downloaded Open Office Calc sheet.
I wish to use code letters in a column but every time I type 'a' it gets 
changed to'A'
When I start typing an image name it auto fills with something else I don't 
want.
Please how can I disable all auto-fill operations?
I have searched in vain through the menus.
Regards Peter