Just a HD file on your Hard Drive?
If so, all you need may be the proper splitters if it is in MKV format. \
MP4 should be supported nativly, but sometimes theres issues if AC3 within a MP4 container.
Shark007 codec pack would be my recomendation, as it does not make associations or alter what Windows 7 has going by default. But will allow playback of most anything in WMP12. Not to mention Shark is a trusted member of our community.
Found here: Shark007.net - Windows 7 Codecs - WMP12 Codecs
If its the actual Bluray Disc, you will need software such as PowerDVD for example (although there are others) and a HDCP compliant monitor/Video Card.
the quality of the video itself however will be dependant on a few factors, such as the codec used to encode, resolution,bit rate, and most importantly settings the encoder used.