Greetings

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This is a setting that can be set by malicious software and that's why Malwarebytes' detects it. However, since you recently reinstalled it's doubtful that this was caused by any sort of infection (particularly if you're using Windows Vista as this setting is the opposite in XP from what it is in Vista, hence the reason that Malwarebytes' detects it, because it doesn't differentiate between the differences in default settings between the two versions of Windows). For more info and an incredibly long read please have a look
here and it should sufficiently explain why the detection was made and what it means.
As for your updating issues, this can be fairly common, especially when Windows Update attempts to download and install large numbers of updates at a time, which is exactly what happens when you check for updates on a newly installed system. As long as you reboot when told to by Windows Update and check for updates again repeating the process until it shows no updates available then you're fine. If you have further issues or errors with Windows Update because a particular update or updates won't install or download correctly please let me know.
Also, please be sure to install an antivirus program to protect your computer as both Malwarebytes' and SUPERAntiSpyware are designed to compliment the protection given by an active antivirus, not to replace it.
If you need anything else please let us know.
Thanks

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