I've been running various versions of WIN 8 (now 8.1) since the very first technical preview without a hitch until the recent roll up about a month and a half ago (for WIN8.1 pro 64 bit). That gave me an instant and terminal BSOD, which I haven't seen the likes since WIN95. As a 20+ year IT veteran, I tried every tool in my bag of tricks, but even though the boot partition was healthy, it wouldn't boot. And since it was an upgrade, the original install disc as well as the repair disc I had made wouldn't work either. Neither even recognized the then working WIN installation. Of course according to MS's licensing agreements, I had to relinquish licensing of my old OS when I upgraded, so I couldn't revert to that either. Called MS support to no avail. Their solution was for me to purchase tech support for $150 (with no guarantees), which I wouldn't do since I didn't have that kind of spare change lying around, but mostly because it was an MS update, not something that I did, that created the problem in the first place. So I gave up trying to reinstall 8 and tried a tech preview of 10, which works fine, except all my licenses now come up invalid since I used their keys in the previous installation (Office, Expression, and other MS products, plus dozens of other programs including Adobe Master Suite). This is a real pain. I have legitimate software worth thousands of dollars that I can't use any more. Not to mention the hassle of trying to build from scratch nearly 3 TB's of data and programs! All I can say is Linux is looking better and better.

I do not recommend that you use the Windows 10 Tech Preview as your normal OS. It may timebomb at a certain date and become unusable.

Hello blilling,

I can understand your feelings.

If the computer is OEM Windows 8, about the license issue it is recommended to contact the manufacturer.

If you have the Retail version of Windows 8. Do you have the license key?
If you have it, please try to active your computer by the key.

If you still have problems about the retail key, it is recommended to contact the license phone support.
http://www.microsoft.com/licensing/existing-customers/activation-centers.aspx

Best regards,
Fangzhou CHEN