I have installed Ubuntu 14.04 LTS alongside the Windows 8.1 through the installation guide provided by Ubuntu but I cannot see the grub on the screen whenever the computer boots up to select between Windows or ubuntu. Therefore I cannot run the PC with Ubuntu which I have installed. here is the Boot Repair report link http://paste.ubuntu.com/10178568/ please help me with this issue thanks
What brand/model computer? Many brands now modify UEFI to only boot a "Windows" entry in UEFI, but will boot the hard drive entry, so we have to copy grub or shim into the efi folder so system thinks it is booting the hard drive.
But you have installed Ubuntu in BIOS boot on an UEFI system. To easily dual boot you need to have Ubuntu in UEFI boot mode. Boot-Repair can in its advanced mode uninstall grub-pc(BIOS) and install grub-efi-amd64(UEFI). But you must boot in UEFI mode to convert.
Shows install with screen shots for both BIOS(purple) & UEFI(grub menu), so you know which you are using.
It also looks like you had an UEFI boot and had run the old version of Boot-Repair that renamed the Windows efi file. Boot-Repair does not do that any more as there now are better ways. But you need to undo the rename. Not sure if new copy of Boot-Repair will do that or not.
This was the original Windows UEFI boot file: /EFI/Microsoft/Boot/bkpbootmgfw.efi
And a grub or shim file was copied into the Microsoft folder and renamed to this: /EFI/Microsoft/Boot/bootmgfw.efi
You want to fully backup the entire efi partition, just in case and rename bkpbootmgfw.efi back to bootmgfw.efi. then you should be able to directly boot Windows from UEFI menu.
If an HP or Sony you may then need to copy grub or shim into /EFI/Boot and rename it to bootx64.efi.
If you need more detail, already posted here: