Installed on slave drive and failed........ Help!

Not sure where to look for this problem here on the forum. I am hoping that it is an easy fix and some here can help out. Yesterday evening I was attempting to install and ISO of windows7 onto a friend of mines computer. he has a legitimate copy just no disk. His comp will not boot to the USB and his Optical drive is trash. Without doing the proper research. I decided to connect it to my system also running a legitimate copy of window 7 and install the ISO from my system to his drive. Everything seemed to be working. The disk installed took the OS and booted from his drive. When I celebrated in success and installed the drive into his system, it failed to boot asking for boot disk. My system shows two boot options for windows, only one works the original install. The bad thing is that now it is saying that I do not have a valid copy of windows. I am trying to avoid having to buy a copy that I have already purchased. Does anyone have an idea of what could have happened and if there is a fix for it ? thank you for your time.

When you installed to your friends HD in your PC you didn't unplug your HD so it placed his boot files on your HD WIn7 partition to create the Dual Boot. You can remove his boot listing in your msconfig>Boot tab.

As to his HD it lacks its boot files which can be repaired by Marking Win7 Partition Active
with Option 3 from the booted Win7 Installation media or System Repair Disk Command Line.

Then run Startup Repair - Run 3 Separate Times. It may still not start though but stall on the 7 start animation due to needing all the drivers changed. We have a bootable CD of Paragon Adaptive Restore which will adjust this but you have no CD drive in the target PC.

So I would start over with a fresh ISO for his licensed version (in 32 bit if 4gb or less RAM) using the tool provided to write to stick, from Steps 1 and 2 of Clean Reinstall - Factory OEM Windows 7. Then set his HD to boot first in BIOS setup, trigger stick to boot using one-time BIOS Boot menu key listed on first boot screen. Then proceed with those same steps in the blue link which will provide a perfect install, and the tips to maintain it that way.

If your activation has somehow failed it must be from some other action, so check at Control Panel>System what the status is and report back. If you see the Activate Now or Change Product Key link active, you can click on it to insert your legal product key.

Great thanks I will get working on it now. One thing I don't have my product key. Looks like I am screwed but I my still be able to get him up and running. I will report back when I have completed the steps. Thank you for the info.

Try to audit your Product Key now with Belarc Advisor, and then Magical Jellybean keyfinder to confirm.