Firstly, not many laptops come with two hard drives. Even so, two hard drives isn't the best solution, so I'd mothball it.
So what about the 'two partitions' idea? A user could install all programs and store all files to a separate partition which he/she only has permission to access (by configuring the security settings in Windows). The benefits? Other users can't gain access to the partition, and if the OS partition needs to be formatted, then the user files will be intact since they're stored in a separate partition. However
, a separate partition is unneeded to achieve your goal. What about the other user's files and programs? Will you create another partition and have three partitions in total (OS+partition1+partition2)?
The simplest solution
is just to have one partition (the OS partition), and instead of installing programs to a public directory (e.g. 'c:\Program Files\
'), install the programs which you want exclusive access to in a private directory which you only have permission to access and modify. Other users will not be able to access any of your programs which you've installed into that private directory. For this to work, each user must have a user account that is passworded, and set as private
You can create such a directory and modify the permissions, or simply just install the programs to a private directory which already exists, this being 'c:\Documents and Settings\*User*\
' where *User* is the user's account name in question. Create a new directory in that folder such as 'Program Files' and install your programs there.
Similarly for personal data files, as long as each user stores his/her files to a directory within the 'Documents and Settings' user account folder, then other users cannot access those files. For example, the 'My Documents' folder resides within the user account folder, therefore all files inside that directory can only be accessed by that one user.