Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have 2 storage drives, one is a hard drive and the other is an SSD.

I used to run windows on the hard drive, and left the SSD untouched. but then I installed another windows copy on the SSD (which has the E:/ letter).

The drives currently are:

C:/ [Hard Drive] Has old OS

E:/ [SSD] Has new OS

I'd like to make the new OS (SSD) as the primary drive, therefore having the C:/ letter instead.

I tried switching the old C:/ to H:/ and then switch E:/ to C:/ but it said: Invalid parameter.

Anyone has an idea how to do this?

P.S. I really don't want to reinstall E:/ again if possible.

share|improve this question
Have you tried booting into a Linux distro and tried switching them around, in my experience, gparted offers more versatility compared to Window's Disk Manager. – Zain Patel May 28 '13 at 14:13
Change your boot priority in your BIOS, it has nothing to do with what the OS views as which. @ChickenP's suggestion is a wild goose chase for this particular type of issue. – nerdwaller May 28 '13 at 14:14
Try booting to a GParted disc. More then likely the reason your getting invalid parameter is because your attempting to modify the drive letter of the operating system your currently using. – MHrappstead May 28 '13 at 14:16
You may need to update your Windows 7 boot loader after changing the drive letters. – MHrappstead May 28 '13 at 14:18
Switching the drive letters doesn't mean you switch the drive. You need to actually boot into the new OS to have it be recognized as the C:\ drive. – Kruug May 28 '13 at 14:34

Unplug the "old" OS hard drive and plug your new SSD into that same cable. Don't plug the "old" HD into anything. Does the computer boot onto your new SSD?

If it does then plug the old HD onto the other cable and you should be good to go. If it doesn't boot, then you'll need to fix the boot loader on your SSD. Load up your Windows 7 disc and select the repair option. It'll fix this for you. Once this boot loader is fixed, now you can plug your "old" hard drive into one of the other SATA cables, and you should be able to access your old data from the new SSD-booted OS. I'd advise taking what you want from the old drive, then doing a full format of it.

share|improve this answer

Check your BIOS boot order. Make sure the SSD is set to boot first.

share|improve this answer
Tried it, doesn't do anything unfortunately. – user23392 May 28 '13 at 14:14
@user23392 - That may mean you don't have a bootloader on the disc or you are choosing the wrong one. You should expand on "doesn't do anything" - do you get an error or what? – nerdwaller May 28 '13 at 14:15
Did you install the Windows 7 OS onto the SSD using the same computer? If not Windows will not load because the OS expects to see the same motherboard. – MHrappstead May 28 '13 at 14:22

Using DIKSPART in command prompt (run as administrator). In here you can simply assign letters by running list disk and select disk 0 and then list volume select the volume you want to change and then use assign letter C to change the letters to what you want.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.