Yesterday I picked up my guitar and as soon as I tried to play it I got loads of fret buzz.
I haven't adjusted it, changed the strings or anything recently and it was absolutely perfect the day before. It is an ESP Ltd Viper 200FM and I've only had it for 6 months so I doubt the problem is down to wear.

Does anyone have any idea what could have caused this problem and how I can fix it?
it`s probably down to the fact that the last few days have been cold and wet in the uk, and temperature and moisture can cause subtle changes to a guitars setup by affecting the wood(don`t panic your guitars not ruined), read the setup sticky thread, check the neck relief if that`s ok raise the action 1/4 turn.
i've got a esp ec-cz buzzing also its always done it since i've gotten it but haven't fixed it yet.. now its starting to bug me