The b0 error tells you that the BIOS can not find a boot loader on the hard disk. Are you sure that you have disconnected the new disk? And put the correct cables back on to the original disk? If you are absolutely sure that you have then you can try to do a repair boot by inserting the Windows install disk (Windows 7 and Vista) and select repair and then fix boot problems. For Windows XP you will have to enter recovery console and do a manual repair.
Upon rereading your original question which is not clear, if you can boot with the new disk disconnected and get the B0 error when you connect the new disk then you need to enter the BIOS and select which drive you wish to boot from which should of course be the old one.
so I added a secondary hard drive, my primary hard drive is in sata port 2 and is second on my boot order after the cd/dvd drive. The hard drive i added is on sata port 4. This is all i did as far as setting which hard drive to boot from. Did i miss a setting?
when i started up the PC i recieved the b0 error, so i unplugged the hard drive i added. So im where i started with only my primary hard drive connected in sata port 2. Then i restarted, but still got the 'b0' error. i cleared the cmos and still get the 'b0' error.
I don’t know what you did to corrupt your hard disk, perhaps you are not saying everything that you did. One option would be to reinstall your operating system another would be to try and repair the boot sector with the tools on the operating system install disc. Before you do this try doing a scan disc with the utility on the system install disc.