I HAVE A DESKTOP PC WITH ONE SATA HD, I WANT TO ADD ANOTHER SATA HD FROM MY DEAD LAPTOP, WHEN I DO THAT MY PC WONT BOOT AT ALL....THE SATA HD HAS WIN VIST AND DESKTOP HD WIN 7.....DO I HAVE TO SPECIFY ON BIOS WHICH ONE IS MY BOOT DRIVE SLAVE ETC...LIKE IT WAS WITH IDE DRIVES....I WANT TO BE ABLE TO USE EITHER ONE DRIVE..THANKS JAMESTK@HOTMAIL.COM
It should remember your desktop HD as your boot drive if you have not changed the boot order.
While that is true in most cases I have seen mainboards that seem to change the boot order when a new drive is found. The drive from your dead Laptop is not going to boot in your desktop you will have to re-install the OS on it. Windows does not like mainboard transplants and in most all cases will not boot. The first place to start would be to go into the BIOS and make sure the main boot drive is set correctly.
One last thing if Vista came with the Laptop then it is keyed for that Laptop and as with any Windows OEM OS it is not transferable to another computer.
If you had specified which MB you had, there may have been a real quick check.
For example: on Gigbyte MB you can hit F12 and it would bring up a boot menu showing the two HDDs, your CD drive, plus a couple of other options that you may not even have. On my Asrock MB it is F11 that brings up this Boot menu.
If thi is a possibility, you could then select to continue to boot using your Win 7 HDD. Once in Windows you would see your "old" laptop drive and you would be able to reformat it. Then Reboot, enter Bios and set boot priority to the windows 7 HDD.
Side comment: Should not post in all caps - it's considered Yelling and should never post your emal address in a public forum.
Hope this helps and straightens your problem out - If So - Enjoy.