Log in your spare account and change the password there.
-> Because of UEFI, "secure boot" and more the usual free tools may not work. So you've off to www.lostpassword.com it seems.
Again (for the nth time in over a decade), always have a spare admin account.
Bob
hi i have a toshiba pro c850 1gr...i use windows 8. i turnt it on and my icon appeared with my name but it also says locked..i have never set a password on it, so i am stuck as what to do now!...please can anyone help me.

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