Try this
go to settings....
go to Applications...
go to Manage applications...
Scroll down till you find “Google Apps” click on it...
Simply hit the "Clear data"....

ALL YOU CONTACTS AND EVERYTHING GOOGLE RELATED WILL BE GONE

Now navigate back to the main settings window and go to Online service accounts...
Google should be free for your new account inputs.

Hope this helps.

 

What happens when u cant remember the email o user name or unlock your fone ? what shd i do?

 

On a similar note, is there a way to stop Gmail from syncing your email contacts onto your X10 contact list? Any time I load Gmail on my phone, it automatically syncs these and then after I have to remove them from my phone each time. Just wondering if anyone knows a way to stop it from doing this. (I've tried the Gmail settings and looked through those on the phone as well to no avail)

 

go to settings -> data synchronization -> google sync -> de-select contacts.