Sadly we dont have anyway to do this. You might be able to follow the instructions here:
http://arstechnica.com/business/news/2009/12/-the-usb-flash-drive.ars
That might allow for this to work.
If the update was downloaded, it was for Vista and there is no reason to go to Win7 like the person from HP Said. They are just trying to sell you something. If the Memory Diagnostic failed, that means you have bad RAM and replacing it
should correct your issues without having to update to Win7. Adding more memory wont solve the issue but replacing it as a whole should.
You will not have to reinstall Windows but you could just jump to Win7. You can use a friends
disk, but you have to purchase your own copy to have a legit serial. The Disk is not tied to the serial in use. You wont have a serial for activation and will only have 30 days to use the software before it locks down on you. Purchase your own copy to prevent this.