First steps

• Find a Windows 7 or Windows 7 SP1 CD or ISO file
• Insert the CD or copy the ISO to /storage/isos
• Create a new guest, with at least 1024MB of RAM for a 32 bits install, 2048MB for 64 bits (https://support.microsoft.com/en-us/help/10737/windows-7-system-requirements)
• Install Windows. It's usually a good idea to choose "Ask me later" when asked about Windows Update, to avoid interference when installing standalone updates below.
• Download the OpenXT tools certificate (for openxt.ainfosec.com builds, use: http://openxt.ainfosec.com/certificates/windows/developer.cer)
• Open an Administrator command prompt, cd to the directory where developer.cer was downloaded and run the 3 following commands:

• bcdedit /set testsigning on

• certutil -addstore -f "Root" developer.cer

• certutil -addstore -f "TrustedPublisher" developer.cer

• Reboot the guest
• Insert the OpenXT Guest Tools ISO, install the tools and reboot

Installing SP1

Non-SP1 installs of Windows 7 should be upgraded to SP1 first.

Out of the box, there's a chance that the SP1 installation will never finish. The following steps should address that:

• Install KB947821
• Run the SP1 standalone installer: KB976932

Fixing Windows Update

Again, out of the box, there are Windows Update issues in WIndows 7 SP1. These are not OpenXT-specific, but they seem to have a bigger impact in Xen guests than on bare-metal.

Microsoft released many Windows Update fixes over the years, and after some testing, the following ones seem to do the trick (install them in this order, using the standalone installers, not Windows Update):

1. KB3102810 (Make Windows Update a lot faster)
2. KB3020369 (Dependency for 3.)
3. KB3161608 (Includes KB3161647, which fixes Windows Update hangs) See http://www.infoworld.com/article/3099109/microsoft-windows/microsoft-yanks-buggy-speed-up-patch-kb-3161608-replaces-it-with-kb-3172605-and-3172614.html
4. KB3161664 (Suggested by http://superuser.com/questions/951960/windows-7-sp1-windows-update-stuck-checking-for-updates. May not be needed, but seems pretty good to have seeing the description!)

More up to date list 10/13/2016:

1. KB3102810 (https://support.microsoft.com/en-us/kb/3102810)
2. KB3020369 (https://support.microsoft.com/en-us/kb/3020369)
3. KB3172605 (https://support.microsoft.com/en-us/kb/3172605)

Updating

Once Windows Update is fixed, you should now be able to select "Windows Updates" in the Control Panel, check for updates and install the appropriate ones.

At this point, you can also configure Windows Update to automatically download / install updates.