Windows 7 Failed Custom Windows 7 Install on New HDD (Boot Mgr Missing followed by installer not recognizing H


New Member
I just put together a brand new PC build with all new components. In the middle of a custom install of Windows 7 on the HDD (the system only has one 1TB 7200rpm toshiba HDD), the installation screen went blank and the computer restarted. After restarting, the monitor displayed bootdisk mgr missing. So I went into my BIOS and had it boot from the windows install disc first and tried to re-install windows, but now the Windows installer isn't recognizing my HDD. I also tried switching the drive to a different sata port, but that didn't help. Finally, I tried setting the drive to AHCI mode in the bios, but after restarting the monitor only flashed a white underscore in the top left corner... So needless to say, I'm pretty worried and don't really know what to do at this point. I turned off the computer and haven't touched it since.

I should note that this was my first custom-built PC. I am fairly sure that everything has been installed correctly as I am able to get to the BIOS and it recognizes the HDD and Optical drive and everything else seems to be up and running properly, but if this is a hardware issue, I would like to try to find out ASAP so I can return the parts.

I can provide more specific information about my system's specs and the situation if needed.


Excellent Member
Microsoft Community Contributor
You cannot rule out the possibility the new hard drive could have a problem. I have had two like that in the last 3 years.

You say you tried putting the hard drive controller in the bios to AHCI... Was the board not set up by default for AHCI, and if it was, is there some reason you wanted to change it?

A blinking cursor on the upper left usually means it is not finding the OS install. Sometimes that can be caused by the bios not directing the boot to the correct place. Since new motherboards may come with a UEFI bios, do you happen to know if you installed in a UEFI configuration or Legacy (MBR)? It would make a difference if you set the bios to look for a Windows Boot Manager (UEFI) or just the hard drive (Legacy).

It sounds like your system is doing OK, just a problem with the hard drive or its setup. Those SATA connectors are delicate and might check to make sure the connection is all the way on the plug. Make sure you have it connected to the primary SATA connectors and not any special SATA controller ports. Many boards have 8 SATA connections and the first two are the Special controllers. Any questions about this, info about your motherboard and system might help us find out.

You might also try taking the Install DVD out during the first reboot, it isn't needed for the rest of the install. Watch out for your fingers...the tray may try to close quickly when open.

It may be a good time to familiarize yourself with the special F keys. The one for the Boot Device menu comes in very handy so you don't have to change the boot device in the bios when you want to boot to a DVD.