I have a "Recovery" partition which I mistakenly thought was redundant after reinstalling everything to C:. "Recovery" was previously the "Active" partition. I set C: as the "Active" directory in disk manager (I am using Windows 7). When attempting to boot, the laptop now returns "BOOTMGR is missing".
I can go to BIOS and mess around with some stuff, but haven't found a way to change the active partition. I can disable various SATA drives (four are listed) and doing that sequentially changes the error message on booting, but no combination lets it boot.
I am travelling and don't have a USB key or bootable CD with me. I do have an external HD, but this other computer that I'm on right now (which is unusably slow) doesn't recognise it.
I think that the easiest solution will be to get hold of a USB key, make it bootable, and sort out the active partition from DOS. Any glaring shortcuts, alternative solutions or likely obstacles I'm missing?
Edit: I now have a USB key, can boot to DOS and run fdisk, which I expected to enable the active partition to be set. Unfortunately fdisk will not set NTFS partitions as active, and I haven't found any alternatives that run from DOS and will set NTFS partitions as active. At this stage it looks as though I will need to get Windows CDs as Olivier mentioned below.