Within how many years should one complete LPN in Minnesota??

I graduated in Dec 2006. Since then I appeared for the Nclex-PN twice but couldn't make it. I know that one can take the Nclex-PN any number of times until you pass (54-90 day period). One of my friends lives in Illinois and she told me that she should complete LPN within 3 years in their state. So I was wondering within how long should the Nclex-PN test be finished from that day you started the LPN program in Minnesota? I thought that it was 4 years but I'm not sure. So is there a limit or not?? I also heard that if you don't complete LPN within 4 years, you have to redo the whole program again from the start. So is this true?? If any one has any idea please help...