no boot device available error

[oneely]

I accidentally erased the boot sector of the C: drive in my new Dell computer while trying to format a new drive that I had installed. I know this WAS STUPID but it was late at night and I was tired and careless. Now I an looking for a way to recover.

What I get on startup is the following:
No Boot Device available
Strike the f1 key to reboot, the f2 key to run the setup utiity
SATA 0: Installed
SATA 1: Installed
SATA 2: Installed
SATA 3: Installed
MSATA 0: None

To recover I followed the following procedure. I created a bootable USB drive with Windows 8 PRO ISO, (which is my installed system, using Windows 7 USB DVD Download Tool and bootsect.exe), on it.

My intention was to use the repair function and other tools to rebuild the empty boot sector on the C: drive. My system will not boot from the USB drive, so I used set up and made the USB drive 1st. I still get the same error.

After several attempts of rebooting I get an brief line that says This computer has failed previous reboots at checkpoint [00A2]

I have looked at the boot menu (f12) and run the complete diagnostics which runs for several hours and returns no errors.

The boot menu (at f12) says that the Boot Mode is set to UEFI; Secure Boot : ON
The change options are:
Legacy Boot Mode, Secure Boot off
EUFI Boot Mode, Secure Boot off

I don't understand what these options mean or if I should change anything.

Any suggestions

 

[dodger46]

Whilst UEFI Boot Mode (Secure boot on) was probably the original setup for W8 it may be preventing you from booting from your W7 prepared Repair disk. As you only need to get to the Command Prompt I see no reason not to try with Legacy Boot (Secure boot off) then reverse the changes once you've repaired the Boot Sector.
Was the procedure you used to create the W8 ISO/USB similar to this one?
http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media

 

[oneely]

Whilst UEFI Boot Mode (Secure boot on) was probably the original setup for W8 it may be preventing you from booting from your W7 prepared Repair disk. As you only need to get to the Command Prompt I see no reason not to try with Legacy Boot (Secure boot off) then reverse the changes once you've repaired the Boot Sector.
Was the procedure you used to create the W8 ISO/USB similar to this one?
http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media

 

[oneely]

Yes that was the procedure I used. Legacy boot worked! Now everything is recovered and working well. Problem Solved! Thanks!

One problem though. when I switch back to EUFI boot mode after everything was fixed, system would not boot, --same error messages as at the start.
I switched back to Legacy and it is fine. Guess I'm stuck there.

 

[dodger46]

Yes that was the procedure I used. Legacy boot worked! Now everything is recovered and working well. Problem Solved! Thanks!

One problem though. when I switch back to EUFI boot mode after everything was fixed, system would not boot, --same error messages as at the start.
I switched back to Legacy and it is fine. Guess I'm stuck there.

Well, Windows 7 is supposed to support UEFI boot, but obviously in your case it doesn't. Whether that is the fault of the UEFI or the boot software, who knows? Meanwhile I doubt you'll notice that great a difference in performance...