Dell Inspiron 15 3558, changed boot mode to Legacy and back again, now it can't find the OS

[iron_jack]

As per the title, I changed this laptop's boot mode from "UEFI - Secure Boot" to "Legacy" in order to do a boot-time virus scan from USB (with ESET - it didn't find anything fwiw).

However, when I changed boot mode back to "UEFI - Secure Boot", it says it can no longer find any OS.

When I use a Win10 disc to boot into rescue mode, if I go into the command prompt and use dir, I can see that all the files are still there, so the drive hasn't been wiped (thank god) or anything.

I've tried using Win10's default "Startup Repair" option, which doesn't appear to work. I've tried using bootrec /fixmbr and /fixboot, and even /rebuildbcd, none of which are helping it find the OS.

Any thoughts?

 

[webworkings]

Try the following...

1. Power off the laptop.
2. Power on the laptop.
3. As soon as you see the rotating loading circle, press and hold the Power Button until the computer shuts off.
4. Repeat this process a few times until you see the "Preparing Automatic Repair" screen.
5. Now you want to let the laptop boot to the "Automatic Repair" screen.
6. Click "Advanced Options" and then select "Troubleshoot".
7. Here you want to select "Refresh your PC", if you do not wish to erase data, or "Reset your PC" to erase all data and restore your system.
8. From here just follow the screen instructions until the recovery is completed.

NOTE: You will need to get into the "Advanced Options" in order to get the "Refresh Option". This choice will keep your data, but any programs installed will be lost.

Do not do a "Reset" as that will wipe all data you have on the laptop.