You need a Blu-Ray drive, which I expect is default standard these days, and enough video RAM, which I imagine more than plenty is also provided as standard. Otherwise, whether it’s Windows 7 or not is, as far as I know, irrelevant.
Windows 7 fully supports Blu-Ray if your computer has a Blu-Ray drive. Macs on the other hand cannot play Blu-Rays without third party hacks because Steve Jobs won’t allow it.
If you’re going to be watching Blu-Ray movies you’re also going to need to buy third-party software. Windows Media Player does NOT support blu-ray, perhaps this is what your friend was referring to when he said Win 7 does not support Blu-Ray. I’ve read that WinDVD works well with Blu-Ray playback.
As far as I can tell there is not a freeware media player capable of Blu-Ray playback - yet. I expect VLC will get there eventually.
Also be sure your box has the hardware capable of playback. You’re going to need an HD video card. ATI 2400HD or better or Nvidia 8xxx or better. You should be fine with most any recent dual core processor AMD or Intel. Furthermore, you should have a High-def monitor or you’re wasting your time to begin with.
First off its not a DVD its a Blu-ray, second you need a drive that can play BD, it will usually tell you. Than you usually need a pay software to play the movies, the encryption on the movies usually means only certain software will play them like PowerDVD. Most drives now adays are still not Blu-ray by default you usually have to do an upgrade. Make sure your video card can go to at least xxxx by 720, my computer is 1920x1080 so i can play 1080P movies