We cannot help you with this question. Windows 7 is sold by Microsoft Corporation and it is NOT free. If you wish to install a new copy of windows then you will need to purchase it through Microsoft or an Authorized Retailer that will sell you a copy of the software with an activation key.
Yep, no more trials, as the days of the beta test are long over. Your best bet is to check out a friend's computer, head to an electronics store, etc... if you are curious about W7. If you like it, you can then buy it.