ok. thanks, so is there any torrent download? because i dont see any pause option in the official D3 downloader
I've found that the easiest way for me to install / reinstall D3 is just to download it through my battle.net account. Usually less patching once installed and it wont hound you to register during the install.
If you prefer to use the DVD anyways, maybe try opening the disk and right click on the install file and "Run as Administrator" sometimes that helps. Also, make sure any anti-virus your running isn't interfering.