Unwanted System Administrator account

[G Keeler]

Today I ran Microsoft Baseline Security Analyzer and discovered a system
administrator on my computer that I know nothing about. The user name is a
long string of digits, letters and dashes. How can I remove this
administrator account from my computer???
Thx

 

[G Keeler]

Actually the MBSA shows that there is an account named "Administrator" as
well as a 2nd account called "S-1-5......"