switch users-blue screen

There are 2 users on my system, me and my wife.

When wife tries to switch to her user it goes through the motions and ends
up just showing a blue screen,with the cursor arrow. The cursor moves but has
no function at all.

When I tried to add a new user it went through all that it has to and tole
me it was going to set up the desk top. Screen turned blue and the rest is
stated above.

Can someone tell me how to get out of this bad situation?


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Thank you so much, Mike