are techguys the muppets that work within pcworld stores ? the ones that charge £60 to install a stick of ram ? rip off idiots that charge through the roof prices to do simple tasks where people can just wear an anti static band and do the same thing in 30 seconds for free, or the same company that charge £80 to do a system restore ? what a bunch of mongs, mind you the idiots that pay the prices are more mongs then the workers lol
anyway back on topic,
i think you will find that warranty varies with each different manufacturer if there is a sticker on the case that states "warranty void if open" then you will void the warranty
if in doubt find the warranty paperwork and phone them or look on there website
find out what mother board is inside and look on the mobo manufacturer website to find out whats supported and whats not