My HP envy laptop came with windows 8.1 factory installed one year ago, I did the windows 10 update 2 days ago and it worked fine the first day. The second day I attempted to start my laptop, it failed to start and after an entire day of seeing my computer to attempt automatic repair, I had to do a factory restore. I read that the windows 8.1 product key is imbedded in the IOS but mine seems to be lost. I would appreciate any help with this matter as I have been unable to use my laptop and I have no knowledge of computers. 

Hi,

As far as I know, if your windows 8.1 is a pre installation with HP laptop, we can use Using System Recovery, Factory Reset and Minimized Image Recovery Options to restore and do not need to enter the product key.

Please see these two links:

http://support.hp.com/gb-en/document/c03489643

http://support.hp.com/ee-en/document/c02638587

Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

Hope it's helpful.

Regards,

George Zhao
Forum Support