There are two types of logins, local and network. lets say you had two accounts accounts called lucy, one logs in locally while the other has to first login to the server. the two accounts are totally different and although your domain user contents are still on your computer, since you are not connected to the server at work anymore you cant login. Your IT Administrator will need to go in and take the contents of your domain account, make you a new local user, and transfer your files into it. other than this there is no way to get around it. this is a security method of logging in and no one but your previous job's IT guy is going to be able to fix it. if you cant do this then either you need to login as local administrator to make yourself a new user( your domain users data will be innaccesible, this will be starting from scratch), or reset the administrators password if you forget/dont kno it.