Access files after joining a Domain

Dear all;

We've a workgroup network and now we're implementing a domain, after joining the domain we start coping all files from old users account and put them on D: , then when the user try to access his files on D: or delete any old file he can not.
Then we give them full control on D: drive , but all these things is making headache.
Is there any good way to fix that without facing any problem or other way to copy the files.

Thanks