here is the website
If you need a free trial of windows 7 ultimate edition 32bit and 64bit available
becasuse microsoft don't have a webpage for this even if you need it for trainning with microsoft .
although it says in the training books for windows 7 that you can
Enter for your chance to win* a game hardware bundle
One lucky winner will walk away with a gaming monitor, keyboard and mouse. Two lucky runners-up will score a gaming headset.