@ melott
I know what you mean, I experienced this myself when I bought a OEM Adaptec card. But the most critical software is of course the drivers, and in recent versions of Windows there are usually drivers included for most of the Adaptec boards. That will get you started. Then you will find that the latest drivers for different platforms (including DOS, for use in boot disks for example) are indeed available at the adaptec site.
EDIT:
You should find drivers for your card here:
http://www.adaptec.com/worldwide/support/drivers_by_product.html?sess=no&language=English+US&cat=/Product/AHA-1510A(But WOW, that is an ancient card! ISA and all! :-o Perhaps you should consider an upgrade at once?)
The "EZ-SCSI" software are only available as upgrades from the webpage though ...
