Missing Windows entry in boot loader


Some days ago, I used EasyBCD to add a Linux entry to the Windows boot loader menu on an Acer Windows 8.1 system. Today, Windows installed some updates, rebooted, and ... the Windows entry was no longer in the boot loader menu. This means that I have no way of booting my Windows system anymore. The boot loader seems to boot fine, I get the Linux entry and some Windows memory check, but I can't get into Windows.

Any clues to what I could try? I don't have Windows CDs/DVDs (it came preinstalled and I didn't buy an external DVD recorder just to get recovery discs). Any pointers are welcome!

Thanks for trying to help me out. I still have grub running and I can boot my Linux system through that grub installation. But grub only chainloads the Windows boot loader, which then does not list Windows. I haven't found any instructions to directly load Windows from grub, so I don't think that is possible. The only thing I can think of is to reinstall the Windows boot loader, but I don't know how to do that...
I managed to boot from the recovery partition (alt-F10 during boot), and was able to reinstall the boot loader through the command line. Reinstalling grub was then easy.