Ah, the joys of doing psychology research with modern operating systems.

Any modern operating system isn't going to allow you to access reliable millisecond timing, no matter what you do. You'll need to prempt the kernel to do that, which will require some nasty coding.

There is a company that makes some software that lets you build a real-time virtual OS that runs next to Windows. I have no idea if it works (I'm a Mac person), but it looks like the kind of thing your looking for:

http://www.tenasys.com/intime.html

On another note, make sure the professor you're working with has read this paper:

Ulrich, R., & Giray, M. (1989) Time resolution of clocks: Effects on reaction time measurement: Good News for bad clocks. British journal of mathematical and statistical psychology, 42, S. 1-12.

It basically shows that even older systems that introduced 16ms of error don't really mess with your data. Another useful discussion on RT accuracy can be found here:

http://www.visionscience.com/documents/rt.html

Hope this helps,

-Jon

Aside from OS issues, there are also issues with the x86 architecture. They have a tendancy to lose track of time so to speak. I would think that if someone wanted to create an app that needed extreme time accuracy they would go with RISC based hardware like something from IBM or Sun. Expensive I know, but if you ammortize the purchase over 20 years