hey just missed it! I can give u three methods. Try the 3rd one. Its quicker
1.
Ok wat u can do is, install win 2000 sp4 on d: This will remove win xp pro sp2 from ur boot loader.
Now insert the win xp pro sp2 cd and let it start copying the files. It would ask if you want to install xp or repair it. Just say install at this time.
Now it will start searching for previous versions and give u option to repair it. This time click repair. It will complete the whole installation procedure but ur installed programs will remain intact.
I haven't tried ^^^ this method.
2.
This link might help you
The best trick, i can think is make an image for ur c: , install win2000 and then restore ur c: This shud remove win2000 from the boot menu. Use the above link to add it.
3. try this link. Most appropriate to ur situation
My googling is improving. hehe
BTW cant u install that share broker s/w again?