Date format won't change

I changed Date Format in System settings, pick right format, customised Number , currency, time and date BUT every time I create a new entry (address, activity etc) the date is still in an old format. The system setting shows the right format DD/MM/YY but actual forms keep showing MM/DD/YY.

Don't know how to chnage this or if there is something I've done wrong.

I am quite new to CRM and appreciate any help. We have the version from 2011 (that's the infomation supplied by our provider) so not sure if its the latest one?

Thank you for your help

Monika