Originally posted by Minerva
Secondly, is it possible to add a new harddrive and use it as the master, and change the current one as the slave, in order to access the files for while?
Yes. Generally speaking, the BIOS will first look to the Primary Master drive for an operating system. If it finds an operating system on that drive, it will load that operating system. If you have an operating system on the primary slave, the BIOS will not load it unless it doesn't find an OS on the master drive.
This is the best way to recover data off of a drive with a corrupted OS. If you have a drive where the OS has become unbootable, you can slave that drive to another drive and recover your data then wipe out the corrupted drive and rebuild the drive's contents from scratch.
You are doing the smartest thing by having multiple partitions on a drive; I do the same thing. I only use two partitions, one for the OS and one for my program files and data, but I know people who use three (and sometimes more); one for the OS, one for program files and one for data storage. That way if your OS becomes corrupt, you can format the C: drive without losing any of your program or data files.
I have a 30 GB Maxtor drive and my C: partition is 5 GB and my D: partition is 25 GB. Windows itself doesn't take up much space (depending on the version; 98SE is fairly small, but XP Professional is much larger), but as our friend KidD01 says, a lot of other crap often finds its way to the C: drive, so I never make it less than 3 GB.
If data recovery and data backups are things you're worried about, you might consider running a low-level RAID to preserve your data.