Since the release of the Black Mesa project back in 2012, there is no need to install a HD texture pack for Half-Life anymore.
Black mesa looks and plays better then Half life, and best of all.. it is FREE for everyone to use!

 

It should not be that hard to install Black Mesa, but it appears some people still having problems following the install order for Black Mesa. Just follow the instructions below from the video tutorial, and if you are still having any questions, please let me know.

 

Link: Black Mesa Website