I am running Linux Mint 18.3 and have developed a situation where upon LINUX START UP the sign in Box appears along with a Guest session option above it. However it does not allow me to use my password any longer, because when my mouse arrow clicks in the password box, it immediately goes to guest session mode! and then a pop up tells me all data during this guest session will be deleted. I have searched to repair this issue on-line but all of the fixes seem to require signing in, Which I cannot do! ..Any suggestions for this issue?