Hi, I was wondering if anyone could help me with a guitar problem I'm having.?

My problem is that the 5th/A string of my guitar which is a Peavey Raptor Plus buzzes when i play the string open. I've been playing guitar for 3 years and maybe 9 months ago the string started buzzing. At first it didnt bother me a whole lot so i ignored it. But recently i put new strings on and I would like to fix the buzz. I messed around with the saddle on the bridge moving it up, and also forward and back with the screw on the end of the bridge, but nothing seems to help. I plan on getting a strat sometime this year but i would like to solve this problem. Does anyone know how to fix this?