When you try to install Sharepoint 2013 Server, you will get the message that there still is a System Restart pending from a previous installation.
To solve this issue you can edit a REGkey and continue with the setup.
Open regedit, go to Start and select Run (or use Windows Key + R), and enter “regedit”
Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
Rename the key “PendingFileRenameOperations” to “PendingFileRenameOperations_OLD”
Do not reboot your system, but just run the Setup again and install Sharepoint 2013 Server as usual.