Finding a Thesis.

Hello,

I am new to the forum and was looking for some help to suggest a thesis for my next paper due in a few days. My previous paper was a Compare and Contrast on Mac Vs. PC which is my subject. My next paper is using the same subject but now I have to come up with a thesis and write a Cause and Effect essay on the subject. I am totally stumped on what would be a good and extensive thesis to produce a cause and effect using Mac and PC. When I wrote my compare and contrast essay my conclusion favored towards PC. Thanks in advance for any help.