With Windows especially this doesn't work. It may have done way back, with Windows 3.0, but from Windows 95 onwards it has usually failed.
The problem is that the installation procedure not only creates "Program Folder" files, but also inserts system files and others elsewhere on the system, eg in the Windows\System, Windows\System32 or Windows\SysWow64 set of folders. There's no way around that as this is how Windows works, sharing files amongst applications. In addition, the install procedure makes numerous entries into the Windows registry.
This means that, if Windows is ever reinstalled, those files and registry entries are lost and cannot be replaced. What we have to do after a reinstall is to install those applications again. So, keeping the software Setup CDs, or if downloaded from the internet, the downloaded Setup files, safe and secure, is important so you can install those applications again.
So for those reasons I see little reason to install software, applications, etc onto a different drive. I have also seen talk in these forums that 'seek' times suffer when the OS has to search other disks for data. I may have that wrong, so I will stop that comment there.
Even partitioning a hard drive into two or more partitions doesn't safeguard installed applications, for the same reason.
You could look up "Cloning software" and see if there is anything that would help you there. But other than that the best way is to "have a plan" for if and when you need to reinstall Windows. Save the installers and work through them to install the software again.
I hope that helps.
What I plan to do is buy two hard drives, one for windows 7 and one for all the programs that I install. The main goal is that I will be able to reinstall windows 7 without having to reinstall any programs. Is this possible? If so, how is it done. (I know how to install programs to a different drive but not sure that they would be usable with a fresh build)