"that is suitable for windows operating systems"

Which one specifically.

A high-end computer is not necessarily a compatible computer with certain companies hardware & softwares. You have to know what you want before you know what you want. For instance, a perfect example is Pro tools. Not based upon the best computer but the ones in which they have authorized for use with their hardware & software platform. So what's more important to you playing games on the computer or recording things? Another example is that most software is not designed yet to take advantage of multicore processors or, their operating systems such as the already kaput Vista debacle. Now waiting upon Windows 7 release. Probably why Microsoft is advertising the "Mojave experiment" to try to breathe life into a completely dysfunctional operating system nobody wants. Never mind about giving people in operating system kernel in which they can configure for their own specific purposes such as audio/video production, graphics, gameplaying, Web surfing, etc.. Microsoft is trying to shove everybody into a utilitarian minivan, that does everything for everybody. No choice of boxers or jockeys, pads versus tampons. That's like giving everybody a single microphone technology to use. It's the new communism.

Long live Karl Marx Gates. NOT! I'm getting out of here!
Ms. Remy Ann David

if your lazy, or have extra cash. ADK DAW might be worth looking into. After years of piecing together my own pc's, I said what to heck, and let someone else do it. I have no complaints.

currently my system is
intel core 2 quad cpu q6600 2.4ghz
4gb ram
1024mhz bus speed mother board
os is windows xp.
softwares i use like sonar 6
acid pro

and iv given an opertunity to buy anything especially the computer and mixer that should work for the lets say 4 to 5 years. (mixer should last longer) like now i see adk daw is a kind of site i can get help from .
as far as mixer is concerned i want to know if i buy a good mixer and good mics should i buy seperate preamps aswell, bcoz very good mic pres are also my concern.

your computer specs look fine, but you could upgrade the motherboard and goose the processor up to 3ghz if you are somehow hurting for cpu cycles.
If you have the dough to throw down on a really nice console, you shouldn't need to muck around with outside preamps. Although they can be fun to toy with.