You need to load the drivers while installing windows, by pressing f6 if Im not mistaken. The drives must be on a Cd or usb drive. I assume you no longer have floppy.
If all falis, after all, its a windows install, get a SSD and install vista on it, use the RAID for everything else. You can get a 64GB SSD for 64 dollars at newegg. You dont need drivers to install vista on a SSD
And BTW, dont go with RAID 5, use RAID 0 and have a backup plan. By using RAID 5, if you drive fails, you will need to rebuild the arrey with a new drive before you can acess your data. In the mean time, belive me, 4TB of information will take forever to be rebuilt and in the meand time another drive may fail, causing you to lose everything. a external backup solutuion gives you instant acess to your files right after a crash