Can I start a contest?
Yes, all members can start contests.

I noticed that some contests require screenshots. How do I make one?
On your keyboard, press "Print Scrn" next to F12. Then, open MS Paint and go to Edit > Paste. Then, to shrink it, go to Image > Strech/skew and put 70 by 70 or 50 by 50. It depends on how big the picture is. I use 50by50 since I use a 1024x768 screen resolution. Then, save it and upload it to an image host.