Did you know that when you buy a new pc with an OS pre-installed you have to agree to the terms & conditions before you can use the OS for the first time,  if you don't agree with them you can phone the company you bought it from & get a refund on the price of the OS after returning the backup/install discs, you're then free to install whichever OS you fancy in it's place.

Windows 7 64Bit
Poser Pro 2010 SR1