? of Frustration

Okay, can anybody tell me why a printer will print one document correct, with the same rulers as another, but not print the other one correct. Here's why I'm frustrated...I have decided to print business cards with prizes or rewards for my kids...it's actually cheaper than buying them from the store. Last night they worked well, I printed the first side and then the second, only one sheet out of five messed up. Now I can't get any of them to print the second side right...urg! I've even waited a while before trying to print them again and it is still doing it? What do I do to fix it? Help! And all of this after I was just raving on technology. This blog was done in red because I am steaming hot right now with frustration.