You can reinstall windows as many times as you like using your code, but only on one computer at a time.
Firstly install the ssd like a normal drive, and set it to seconday boot device, with dvd drive first.
Then change your hard drive setting from IDE to AHCI in the bios and boot, insert windows disk and your away.
You can set the drive up to fast cache using both your SSD and 500gb drive, so you bridge the gap between fast drive and large capacity, but will result in slower read and write speeds then using the SSD as primary drive alone.
You'll soon run out of space with a 64gb ssd though, and before long you'll be installing programs on your other hard drive, and will not benefit from the speed boost