I disconnected one of my PCs (Windows 7) from my Windows 2008 R2 domain and restarted the pc. Once I did that, I could not find this account again and could not find the data that was saved in that account. (lost all programs I installed and data like word, excess). Even I could not find them on the hard drive of the PC that is disconnected from the server. How can I get them back?
The data is not lost. The data should be stored in c:\users under the name you used to logon to the domain. If the username existed on the PC before joining the domain, Windows would append .yourdomainname to the end of that user. You may have to use the Windows file properties & security in the filesystem to take over ownership of that users files.
The reason this occurred is that you disconnected the PC from the domain. The user can not be authenticated, as the PC is no longer connected to AD server that verifies the credentials.