Let's not give up all hope just yet.
Do you have any existing components to work with? What spec is your current PC at the minute?
The guys are right no we can't advice building a gaming machine for £200, but i'm wondering if you have anything we could upgrade now and then use in a new machine later?
If you have a decent C2D and a fair chunk of RAM you could look (depending on motherboard slots) at getting a fairly decent graphics card now which would improve gameplay on any existing machine you had, then when you are ready but a new motherboard, CPU and RAM bundle that you could put together with your new graphics card at a later date?
Also can we establish your definition of a gaming machine?
I do have a little pet peeve about some of the comments on here (nothing personal guys). But I just want to check what types of games you want to play and if you are bothered about what settings the game is played on?
I would genuinely quite happily play games on the equivalent of a "cam" copy of a DVD (minus the camera movement and sound synch issues
) Others would only play games at DVD quality while some (a lot of the guys on here) would accept nothing less than better than Blu Ray quality.
The machine you need for a "cam" copy gaming machine is substantially cheaper than a "blu ray" gaming machine.
A "cam" machine could set you back £300 - £400 while a Blu Ray machine you could spend double that on just the graphics card, so more like £1,500 - £2,000.
Although I will stress that I am in a "select few" that would play games on a very low end machine, I just like to double check and ensure people are not mid-led and believe that they HAVE to spend £1,000 + on a gaming machine, I believe you can play most games at just below DVD quality for £550 ish.