Reinstalled to new HD but...

Reinstalled to new HD but...after I put the old HD back in it trys to boot to the old one. After I open the case and unplug it then it boots normally. How would I go about booting to the new drive but have the old one in there (to reformat or delete the old windows)? They are both SATA. I put the one I want to boot form as SATA0 and it still boots from the old one which is SATA1. I went into the BIOS but can't find where you choose the HD boot order. It seems that no mater which SATA slot its in it trys to boot from that one if its connected at all. Even if i disable that slot thorugh the BIOS it won't boot to the new OS unless the cable isn't pluged in. Also, the BIOS seems to be looking for that OS even when its not connected. When I boot up it says its not there and then I hit F1 to continue and it boots to the new OS.

Sorry if this is not the right place to ask this.

 

You can format it from Disk Director rescue CD.