How to change default OS boot disk in Win7

[Kevin11374]

I had a computer running Win7 Pro, with 2 hard drives C (OS boot etc) and D. A while ago, D drive began to show some disk error msg, and so I stopped using it. Recently I got a spare drive from a friend, and trying to replace my old D drive with it. I opened the CPU box and unattached the old D drive, and I restarted the computer and confirmed that Win7 would still run on the C drive only. then I attached the new drive, and restarted the computer again. Apparently the new drive had OS installed on it, and computer started on that new drive. The new drive became C: and the old C drive became D. I tried to switch back to the old C drive by disconnecting the new drive, and got message "missing OS". From the computer property or msconfig I see only one entry "Windows 7".

I really need to boot from the old C drive (with all the applications installed), but don't know how.

Any advice/solution will be greatly appreciated.
Kevin

 

[AddRAM]

Make sure you didn`t loosen the cable or cables from your original drive.

There`s no reason your original drive shouldn`t boot to windows again.

Do you have an install dvd ? You can use that to format the drive you got from your friend.

If not then you could create a Partition Wizard Boot CD to format it. (from/on a working PC)

Bootable Partition Manager| MiniTool Partition Wizard Bootable Edition

 

[Megahertz07]

Windows will assign the boot drive as C, no matter witch disk you boot from.
- Enter BIOS and set your disk as first on boot order.
Boot you system with drive D attached.
Open disk manager (right click on My Computer - Manage - Disk Manager)
Set disk D to inactive so your computer wont try to boot from it.