Windows 7: No OS on restart as comp tries to boot from USB drive.

I built this machine a while back. I have this problem all the time. If I start the already shut down machine everything is fine. If however, I restart or hit reset, I get the "no OS" error. I've discovered that it is trying to load the OS from my external USB 500gb drive. If I unplug the external drive or just shut down completely and restart it works fine. I've fiddled with boot order etc., in the BIOS with no change. How do I get the machine to know not to look for the boot info on the USB drive.?

Just change the Boot Priority in the bios. Your external hard drive must be pluged in so you can tell it the order. I usaly have my hard drives first then DVD/CD then Floppy then Network then USB Devices. Most bios can't go past USB if that is the first drive. For some reason it can't skip it if that is on the top of the boot priority.

In addition you may want to move the data off your external to wipe it using free Partition wizard bootable CD or Diskpart Clean All from the Windows 7 Command Line to overwrite undesirable boot code: Disk - Clean and Clean All with Diskpart Command

Did not work. May have something to do with my initial build. I originally loaded Windows 7 on one drive. Then I got a SSD and loaded Windows 7 on that also. I then had a dual boot of two Windows 7 drives. When I was certain the SSD had everything loaded, I foolishly erased the Windows 7 on the first drive. Not Good. Apparently, (as I learned) the dual boot was on the first drive and in erasing the OS I removed it and the SSD OS could not be found. I was able to find some help on the interwebz to fix this problem and boot from the main SSD. However, as posted, if I restart or reset with any usb drive inserted the machine looks there for the OS. If I shutdown completely, there is no problem on start up.

Please post back a screenshot of your full Disk Management drive map and listings, with all drives plugged including the external and any flash drives you regularly use.

The best method to avoid these problems when you have separate HD's is to unplug the old OS HD during install to the new SSD. Then after install plug back in the other HD, boot preferred OS HD by setting first to boot in BIOS Boot Order, boot the other using one-time BIOS Boot Menu. This keeps the HD's independent to come and go as you please.

We sort these issues here all the time but need to see Disk Mgmt screenshot to see for sure.

Is this the info you need?

Use Diskpart to mark G Inactive following these steps from elevated Command Prompt: Partition - Mark as Active

Then move C to DISK0 position by swapping cables with D, changing BIOS Boot Order so C is set to boot first after DVD drive.

With these changes everythign is configured correctly. If problems persist I would update the BIOS if needed; if not, reset the CMOS: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS

As you USB drive is set ACTIVE, reset to INACTIVE.
Partition - Mark as Active

There is some very useful information and an outline of marking a HDD/partition inactive at Option Two #2 along with other pertinent info in this tutorial at the link below.


Startup Repair - Run 3 Separate Times

Finally got to this today. Made all the changes and everything is working fine.

Thanks