Dell Inspiron 660s with Linux Mint 17.1?

I bought this computer in Jan 2013.  It was loaded with Win8.  I was forced into an update to 8.1, it caused all kinds of grief.  With a Dell tech, it finally was usable again.  It took about 2 days to get it running again.  Fast forward until now.  I changed my Hotmail password, and cannot sign in to my computer in the admin account.  It isn't going to work.  Talked with various people, including Microsoft.  Password reset, and all did not help.  So....

I am very afraid to start from scratch, and start all over.  I saved an ISO from the update of 8.1.  I am going to try to get the Win8.1 back.  If not, I have ordered a Linux Mint cd.  I can only use the guest account on my Dell desk top.  I do not have another way to access the internet.  My intention is to get windows going, then get Linux Mint, and dual boot both.  if I like Linux, I plan to most likely get rid of Microsoft altogether.  I ought to be able to use my own computer password.  I will make a local user account with admin privileges.  I did not know I could do that.  Now my computer which was running fine, is not totally usable.  I cannot get to my pics, or documents, or do anything without admin password, which it won't take.  There is a sync problem or something.  I don't have cell phone with internet, so it isn't synching the new password.  This is a Microsoft failure, and a big one, in my opinion.

Has anyone tried to dual boot Win8.1 with Linux Mint, on here?  I have had a Windows computer since about 1993.  But this has been the final straw for me.  I wish Dell would consider having Linux software, with the Dell stuff on it.  I like the checks and things that you can do with it.  If I load just the Linux Mint cd, I will lose the Dell system checks, that I like.   Any thoughts or suggestions would be great.