I guess it depends on what kind of backup you want.
Fresh Install:
http://wintoflash.com/home/en/
You can install a windows setup disk to a bootable USB flash drive. Either use a desktop which has an optical drive or you can even use your netbook to make it by downloading the appropriate .iso file and mounting it as a virtual drive using something like Daemon-Tools Lite.
You can further customize your install disk by playing around with nLite (
http://www.nliteos.com/) (EDIT: Oh, I'm not sure if this works with Windows 7, you could probably
check this out but I haven't played with it at all.)
Saved State Recovery:
This is what I did with my netbook. I get everything cleaned up and just the way I want it. Then, I backup an image of my harddrive and keep it on a USB HDD and/or on my file server. If I ever needed to go back to a working state, I'll just backup any files that I need and reload the image. Viola, OS and drivers installed. Then I just have to update drivers if any new ones came out since the original image date.
This can be done using a live version of Clonezilla.
http://clonezilla.org/clonezilla-live/liveusb.php As the article describes, download the LiveCD version then install it onto your USB drive.
This method only really works if you have somewhere to put the image... i.e. network share, USB HDD, alternate internal HDD.
Good luck!
