shrinking a non o/s hd to make partition for o/s?

[starlost]

i have a win7 drive that is not c: with one partition. can i shrink it and make space for a win8 o/s. then throw the hd in a new build and install win8 in the small partition? will my large partition of data on the drive be reasonably safe in the new pc?
is this possible? or should i just buy a external hd and backup and be safe?

 

[RealBeast]

Definitely backup your data before starting, at least anything that you would be really unhappy to lose.

 

[starlost]

thanks for the reply