It is possible to have just the OS on one HDD and programs on another, although it isn't necessarily the best option. Most programs, by default, will want to install themselves to the same drive as the OS (C:) and usually in the Programs folder on that drive.

If you have a different drive for programs, you would have to manually change the location for installation every time you install. You may come across some problems where programs need to install files in a Windows folder.

My preferred method is to have the OS and programs on one disk, all data on an other. 10gb is a small drive these days for OS and programs.

Dave

I would buy an external harddrive box, the problem is creep factor if it is a desktop computer, buy better drive, then better sound, then better graphics, etc., 10gb sounds like an old machine, whereas if it is a laptop, they are prone to break anyway so any external harddrive box is a great standby machine because sooner or later a friends says "My comp's dead" and you just say "how much for the scrap" he says "10 pounds" and agree and then take out the harddrive slipping it into the external drive box, so now you have something a little bigger than a USB key, working exactly like a USB key, but with 6 or 10 or 20gb, I now have three 4gb, 40gb and one I bought 80gb.

One last point, if you do get the box, try to get one that has the leather folder it can slip into since the one bad point about all this is that an external harddrive isn't as robust as a USB key.