how to switch between disks without dual boot

Install & update the GRUB.

whs said:

DavidW7ncus said:

whs said:

If they are 2 seperate installations you switch by temporarily changing the boot order in the BIOS. And that is the ONLY way it can be done.

That's not true.
That's what the one-time boot menu is for, to choose a different boot device for THAT bootup, without making a BIOS change.
Also, using EasyBCD can allow selecting the boot OS for a multi boot PC.

That's what I said - temporarily changing. It helps if you read the postings.

I read the posts...
Perhaps we interpret things a bit differently.
You said "temporarily changing the boot order in the BIOS."
To me that sounds like you are saying the OP must go into the BIOS and change the Boot order "temporarily".

Using the one-time boot-menu does not change anything in BIOS - the BIOS Boot order remains the same.
It allows overriding the default BOOT device for THAT session.

I could be wrong here but I don't think you'll be able to boot from the HDD with Windows 7 on at all as it wasn't installed while the HDD was in that particular PC. I'll happily stand corrected if I've got the wrong end of the stick.

No no, the the 2 systems were installed on that pc, just not connected when the other one was installed. But I'll be using (for this pc) F10 where you can (temporarely) change the boot order.

mitchell65 said:

I've just tried that and the disc that had Windows 7 installed on another PC does boot up when I connected it to my main PC. The drivers updated too! That's not to say that it wil always work on other machines though! You would need to try! But this is nott the case in the present situation!

That's surprised me that has. Today really is a school day!

Dave nailed it, EasyBCD is the way to go.