Yeah, Computer Management is so difficult to find. You'd only find it if you right-click on Computer and chose Manage, which is terribly difficult. And then shrinking the C: partition and making a new partition would take, like, several more clicks and some keystrokes. An outrage!

IMHO, no matter what the vendor, multi-boot setups can be a hassle. I suggest a little different approach: yeah, install a second hard drive, but first disconnect your other hard drive(s) temporarily, install the additional operating system onto the new hard drive, then reconnect the old hard drive(s) afterward. Now they're independent of eachother. No bootloader convolutions, no hassles if you decide to get rid of one of the OSes later or one of the drives dies. Use the motherboard's boot-device selection menu to choose the drive (and thus the OS) you want to boot. For my motherboard, an Asus, that means tapping the F8 key at the POST screen. This is how my WinXP / Vista dual-boot is set up.

To the OP: if you'd like to try Ubuntu, you could also install the free Microsoft Virtual PC 2007, then install Ubuntu inside of Windows. A no-risk proposition

Also, you might want to emphasize more clearly that you're specifically looking for software that has stabilization capabilities. I used to use Adobe Premiere Elements quite a bit, and liked it once I got past some of the learning curve, but the version I used didn't know that trick. Maybe the current version does; you could download a trial version if you want to give it a whirl.