help building a new custom fsx rig

Hey, im after some help building a new fsx rig as i sold my pc earlier this year, my old pc was a i7 ready build off the shelf i then added a ssd it ran fsx ok but not perfect. I had uk2000 egnt and i got low fps when landing in the airport with a 777-300er smaller ac were better but still stuttery, i payed 1300 for pc and screen so will be looking to spend between 1000-1400 on a new one, i may pay a little more if its worth it.

so im after your advice i have no real bench mark at presant but im guessing starting with a i7 seems to be a start? I think ill be wanting to oc thr system to have it come already over clocked so need some advice on that too like how much would be enough ghz

Im wanting it to be as real as possible like those as real as it gets videos on u tube in hd? Can fsx really be hd?

Im going to be using pc specilists to build it or if anyone could recommend else where, im from the uk and jetlinesystems dont deliver to the uk

Thanks in advance guys.

I've got a spare PC I never use, you can have it free if you want to collect it, I'm in Plymouth UK, drop me a PM if you're interested.

It cost me £800 about 5 years ago and plays FSX fine.

Its specs are-

Intel core2 E8600@3.33Ghz

3 Gb RAM

Nvidia Geforce 9800 GTX 512Mb

WinXP Home