Turn Windows 7 upgrade to a Normal install?

I had bought windows vista along time ago and when i got it, it had said that i would get a free windows 7 upgrade in the mail when it got released. Well the time has come and passed. I have a small problem where i need to reinstall windows 7 but i cant find my windows vista disc or Serial Key. Now i found a site that explained how to make it so i can just install the upgrade and fool it into thinking that its a normal copy.

http://www.maximumpc.com/article/howtos/how_use_your_windows_7_upgrade_disk_fresh_pc?page=0,0

Now im wondering if this still works and if other people have done it or if there are easyer ways. Keep in mind i cant afford to buy a nonupgrade version of windows 7 atm.