If the windows update option is greyed out and it up at the top it says 'some settings are managed by your system administrator' your computer has some group policy settings which brings up the second question of when you reinstalled windows where did you get your windows disk and did you erase everything or just install on top of what you currently had.
To edit policy setting you may use gpedit.msc (but this is only available on windows 7 professional and higher)
If you just want to edit your settings manually in the registry
Entry name Data type Values
AUOptions Reg_DWORD Range = 2|3|4|5
2 = Notify before download.
3 = Automatically download and notify of installation.
4 = Automatically download and schedule installation. Only valid if values exist for ScheduledInstallDay and ScheduledInstallTime.
5 = Automatic Updates is required and users can configure it.
complete range of Automatic registry options here
Edited by AngryRaisin, 26 March 2014 - 04:02 AM.