When you reinstalled windows, did you do it within Windows?
Here's what I'd like you to do, assuming there isn't anything that can't be replaced on your PC.
Reboot the machine, a black and white screen should come up at some point that says 'Press a key to reboot from disk...' or it may be a choice of Booting Windows with CD support, Starting windows without CD Support, not sure of all the options. I haven't paid too close attention the last several times I've reformatted, it's become sort of instinctual.
What we want here is to completely boot into the windows setup. THis should be a blue screen. There won't be any prompts, but at the bottom of the screen will be a display that will say things like 'reading kernel' and such. It will then ask you if you want to install windows on a partition. DON'T INSTALL IT TO A PARTITION! What we are actually doing is deleting your partitions first, so that you have only 'Unpartitioned Space'. You won't use your mouse for any of this section, just the keyboard. I think you will have to press D, and it will ask are you sure, and press L (L for deLete, in this case). Now you should have only 'Unpartitioned Space'. You will now need to partition it, I want to say F8 to continue. Format it in NTFS, non-quick version. After that, which will take about 20 minutes, you will be able to install to this drive by pressing I, I think. It should be at the bottom (I apologize, again, it's been several days since I last did this and I don't have any more PCs that need reformatting). You should finally (or it should be finally, as you should have reformatted at least a 60GB drive, approximately 20 minute long job) be getting to where it will let you install Windows and will take you to a more Windows-like screen.
After that unhelpful blue screen is gone, you will get to the basic Windows install screen. From here, it is fairly self-explanatory.
I know my instructions aren't the best, but the key here is that it sounds like you just installed and didn't reformat to clear the PC. What we're doing is completely erasing everything and doing a fresh install as if you just bought/built the computer.