Windows 7 - rebooting into different OS

is there an easy way to reboot into a different operating system thats on a different harddrive from the desktop?

Take a look at options EasyBCD.
EasyBCD 2.0 Beta Builds - The NeoSmart Forums

The cleanest way to dual- or multi-boot with OS's on separate HD's is to use the BIOS, as it keeps the drives independent to come and go as you please. EasyBCD interlinks them and makes them difficult to remove.

To do this, set the preferred HD to boot first in BIOS setup, then if you want to boot another use the one-time Boot Menu key given on first boot screen.

thanks gregrocker thats what i do at the mo sugested by you in the past iirc,
was thinking there might be an easier/quicker way to do this so might have a look at that EasyBCD

I guess some BIOS take a little longer to choose the drive. One guy said he had been changing the Boot Order in BIOS setup every time. Didn't comprehend there is a shortcut Boot Menu key for almost every modern BIOS.

I only suggest this because we deal here with a lot of help requests to get out of Dual Boots set up by EasyBCD, which does start up to a nicer Boot Menu. Let us know how the two methods compare for you.