I was getting stuck at 0% or 1% with no results after a few hours it would give me an error. Changed to use my ISP's dns servers and install took about 5 minutes.
I deleted these folders: C:\ProgramData\Battle.net C:\ProgramData\Blizzard Entertainment
C:\Program Files (x86)\Diablo III.temp all the files i could in %temp% changed to my isp's dns servers via network connection ipv4 properties.
Opened a command prompt and ran ipconfig /flushdns
then tried install with 100% success.
Hope this helps someone else.