Fire up regedit. Navigate to HKEYLOCALMACHINE\SYSTEM\WPA. Create a new Key called PosReady. Right click the new key and add a new DWORD with the value 1. That’s it. Now head along to the Windows Update website and you should see a bunch of updates.
This simple hack tells Windows Update that your computer is running Windows Embedded POSReady, rather than Windows XP. POSReady, which as the name suggests is for point-of-sales cash registers, is a variant of Windows XP that was released in 2009 — some eight years after Windows XP was first released. I’m not entirely sure why Microsoft released a variant of Windows XP about six months before the release of Windows 7, but there you go. POSReady will be supported until April 2019.