New Dell OptiPlex 7040 with Windows 7 Pro SP1

For starters, manually set a System Restore point -just to be safe- and then go here to run the Windows Update Fix It for Win 7/Win 8.

Make note of any error messages, if it fails to fix the problem(s)...

Dell use the Downloadable Skylake .iso as the basis of the factory image which incorporates 192 updates more than Microsoft's official 2011 .iso.

Microsoft have been at fault here. Windows 7 has not been able to update from a clean installation for some time.... In the past I recommended users to use the WSUS Offline Update which resolved the issues:

http://dellwindowsreinstallationguide.com/wsus-offline-update/ 

Recently however Microsoft have been making some moves to address the updating issues releasing a Convenience Rollup which is really another name for Service Pack 2 and monthly security rollups.

Dell's Skylake .iso was released 3 months before this Convenience Rollup/Service Pack.

Installing the following with a restart between each.

Windows 7 SP2 Perquisite Update:

https://download.microsoft.com/download/5/D/0/5D0821EB-A92D-4CA2-9020-EC41D56B074F/Windows6.1-KB3020369-x64.msu

Windows 7 SP2 (April 2016):

http://download.windowsupdate.com/d/msdownload/update/software/updt/2016/05/windows6.1-kb3125574-v4-x64_2dafb1d203c8964239af3048b5dd4b1264cd93b9.msu 

Monthly Security Rollup (Install latest Only each Rollup is cumulative):

http://www.catalog.update.microsoft.com/Search.aspx?q=security%20monthly%20rollup%20for%20Windows%207%20for%20×64