I've got the following problem.
A few months ago I bought a Lenovo IdeaPad Y500 and it came with a preinstalled Windows 8. I have shrunk the Windows partition and installed Ubuntu. After the installation grub was loading by default and I could choose either Windows or Ubuntu and they were both starting and running OK. However, since then I was barely using Windows and just booting Ubuntu. Yesterday, I wanted to use Windows, but when I tried to select it from grub it didn't load. So I went to the boot menu and selected Windows Boot Manager and Windows started and was running OK. Unfortunately, after that I lost access to grub, it doesn't load by default and it doesn't show in the boot menu.
I tried using Boot-Repair by running it under USB booted Ubuntu. The first time it was unsuccessful and suggested disabling Secure Boot in BIOS. Here's the log:
So I tried another time, but Ubuntu wouldn't start after disabling Secure Boot (after selecting USB boot it just goes to a black screen). Somewhere I found a suggestion to change UEFI to legacy support and then Ubuntu started with Secure Boot disabled. So I ran Boot-Repair, but it failed again and suggested disabling legacy support too. Here's the log:
I'm out of ideas. Any help would be very appreciated.