Troubleshooting is interactive here. In other words, we give you an illustrated tutorial or step or series of steps and you try them then report back the results.

If you don't understand a step or have problems doing it then you only need to ask back and we will clarify it for you.

If you don't do the steps OR ask back then we assume you are not doing the work. So to report back nothing and then later come back and say you tried everything is simply not believable.

Tell your friend to check if HD is registered in BIOS setup. If not reinstall or check the cables. If that fails then run the HD tests in Troubleshooting Windows 7 Failure to Start.