Are you using windows 10 preview? looks alike //edit 8.1?
How long have you been using it, has it been stable for you - have you had any problems?
I used it for about 1 day and loved it, but it started crashing, couldn't use it at all >(always crashed when I was trying to "log in")
So I had to reinstall windows 7. (working fine now)
>Might be worth of mentioning that I have had some problems with my HDD which might have caused the crashes.