Vostro 660 from Dell, 8.1 installation guide.

1. Start from scratch. Recovery, reinstall windows completely. Answer questions for setup, boot into desktop.
2. Adjust power options to not turn off your computer. Failing to do so will result in failure of windows updates and windows 8.1. Your computer will turn off in the middle of these updates.
3. Boot into safe mode ( run msconfig, safe mode) delete the following files:

x:\windows\SoftwareDistribution\DataStore

x:\windows\SoftwareDistribution\Download

x:\windows\system32\catroot2

1. Msconfig untoggle safe mode. Reboot computer into regular mode.
2. You may now install windows updates. Sometimes it says failure, hit retry until it succeeds. You may need to install all optional updates as well. You may need to install, reboot, check for updates and reinstall reboot until all updates have been installed.
3. Go back into windows update, UNINSTALL KB2871389 and reinstall it manually. Failing to do so will result in the inability to install windows 8.1
4. You may now install windows 8.1

And there ya have it. Thank me later.

Watson