6 years is a lifetime with regard to pc's.. as for the bios.. well thats a whole world of hurt if you get it wrong upgrading it (you can knock out a machine, I've had to blind reflash 2 laptops in the past and thankfully that brought both back).
ah yamaha, I've been helping a friend with his mixing thing.. I said either go midi with it or sell it.. yet more stuff for the landfill that is perfectly fine.. but on the other side the support side is the real cost of this stuff .. so would rather sell you new things
my main pc an i7 is 2 years old now , and I've not really used it so much due to time.. and yep the time creeps up..
I just had to retire my sisters 12 year old single core amd 2600 with a dual core pc that was all of £220 from ebuyer and infinatily faster (obv. I had to get the OS but got it on offer , so wasn't so much.. but win 8..hhmm hehe)
there are a few things that'll check your chipsets etc drivers that'll help . even if the makers site isn't around.