The doing is simple.

The default installation of Win7 should look somewhere other than the system drive to see if another boot system is present, before it goes to C:\ (assuming that's the Windows System Drive). Without being setup this way, you would be unable to boot from an installation disk or a diagnostic disk so having it set up like this is a pretty important maintenance feature.

You can change where the system will look, and in what order, in the BIOS setup that you get if you hold down the right key while the system is starting. Some systems have different keys for SETUP and BOOT ORDER settings, but it shouldn't be hard to find.

You probably could just put a bootable Unix on a memory stick (or on a CD if your netbook has and optial drive) and the machine would boot to Unix if the stick/disk is "in the hole," or to Win7 if the boot system doesn't find something else before it gets to C:\.

It's a little more complicated to set up the machine to stop and ask you which drive to boot from each time you reboot, but shouldn't be difficult. The changes necessary are in the BIOS that's read before there is ANY OS running on the computer.

From the drive/partition sizes given, it would look like C:\ is intended to be for the Win7 system and some programs, and D:\ is for data, but a Unix installation is usually very much smaller than Windows, so you should have room to put it on D:\. While I can't imagine doing much with 350 GB of drive space split between two different systems (I'm getting cramped with 3TB on internal HDs with just Win7 - but I do weird stuff.) it is probably understood that a netbook will not be called on to do too much really heavy duty work - (I hope?).

You may want to look at compatibility of the drive/partition formats. When Windows went "hard for NTFS" I believe that some said that not all Unix systems could read it, although I think I've seen comments that all - or nearly all - can now use it. (Someone can probably tell us about it.) You may also want to look at how much free space is needed for each of the two operating systems. Windows advertising quotes fairly small numbers for the disk space to install the OS but you need about an equal amount of free space - preferably on the same drive - for it to run right. And by default Win7 will only use a "small percent" of the free space available on the system drive (but you can change the percentage, or move the Temp space to another drive, although it's not generally recommended). If you can get both systems up and running, free space questions can be ignored or defered, to be considered later only if you have significant performance problems.

John