i'm working as a system analyst and the usual questions they ask are:
-what prompts a BSOD?
-how to connect a network printer
-user gets a 'page cannot be found' in IE. what are the symptoms?
-what is VPN and how does it function?
-how to map a network drive and etc etc
if unsure, can try www.whatis.com and search the answers there. I did and it's a good website. good luck!