I'm afraid I heavily messed up a laptop (Dell Latitude E5570, running Windows 7 Professional).
Update: I found a way to start Windows … somehow. I'm not sure if running "Startup Repair" from a Win7 disc several times made this possible, if it is due to the steps recommended in the existing answer or if this would have worked from the start, but anyway:
- I enabled UEFI and disabled Secure Boot.
I still cannot add any boot options (see screenshot at the very bottom), so when I start the computer, I just get a black screen stating that no bootable devices have been found.
However, if I hit F12 while booting, the "one time boot options" dialog opens, where I can choose to boot from CD/DVD.
After selecting CD/DVD, I'm prompted to "press any key to boot from CD/DVD". Then: Not pressing any key successfully starts Windows (from the hard disk!).
Still, I'm looking for a fix – but in the meantime, this is at least a functional workaround.
Background: Initially, I suspected an issue with the laptop's RAM due to some spontaneous BSODs. In order to test the RAM, I created a bootable USB stick with Memtest86 and tried to boot from the stick. However, the laptop kept booting the installed Windows 7 instead of booting from the stick, although I set the boot sequence to start from the stick first. Enabling UEFI or the "legacy mode" didn't change anything, nor using the latest vs. the old version of MemTest86.
At this point, I probably started to screw things up: I deleted the UEFI boot options and enabled the legacy mode. After the system insisted that it could not boot from the stick, I gave up on MemTest and wanted to return to the previous boot settings. To this end, I selected "Restore BIOS defaults" and rebooted.
However, Windows didn't startup anymore. Unfortunately, I didn't take notes of all the error messages and steps I took – because I didn't expect this to be such a big deal. Most of the time Windows complained that it could not startup. I also received some error messages that the boot manager could not be found or that "an operating system could not be found". Sometimes Windows tried to start but died with a bluescreen.
To fix the issue, I started from a windows installation CD. As the automatic "Startup Repair" could not solve the problem, I tried my luck with the command line.
Many online resources recommend to use
diskpart and I tried selecting different partitions or volumes (
select partition #no and
select volume #no;
active), but I'm afraid by not really knowing what I was doing I probably made things worse.
I also tried
bootrec /fixmbr bootrec /fixboot bootrec /rebuildbcd
However, the last command reported that no OS could be found.
Following instructions here I ran
attrib c:\boot\bcd -h -r -s ren c:\boot\bcd bcd.old bootrec /rebuildbcd
This did find 1 Windows installation, which I added to the boot list. (Interestingly, running
bootrec /rebuildbcd again finds no installation!)
Still, Windows doesn't boot. Running
bootsect /nt60 SYS /force after a "successful"
bootrec /rebuildbcd didn't help either.
Following these instructions I ran
bcdboot C:\Windows /S C:, also with no success.
I also tried
bcdboot C:\windows /s Z: /f UEFI, following this tutorial. (Not having any "ESP" volume, I might have selected the wrong source volume, making things even worse …)
In-between, I tried running the "Startup Repair" many times, hoping that my efforts brought the system at least into a state from which the startup repair might recover. However, this always reports that the issue cannot be solved.
Below screenshots from the current "status" (sorry, they're in German). If I try to boot, Windows complains "Error: Windows failed to start. A recent hardware or software change might have caused the issue".
I know that some very unwise steps brought me here. I'm also aware, that this is a quite longish question, but I hope it is sufficiently clear.
I'm stuck and grateful for any advice. What is wrong with the startup process and how can I fix it?