I was afraid Shift+Restart wouldn't work fully for you. Your ReagentC said it was disabled. Recently, when mine became mysteriously disabled, I also lost the bulk of the options. I was surprised I got there at all & had any options. Also, although yours does appear to have code for it in your BCD, it is weirdly setup compared to mine. It actually tries to go directly to the Recovery partition instead of setting up a RAM disk. If we get you a fit & proper BCD, all should be well with that.
But I'm getting cold feet. I don't want to put you in an unbootable state. Your BIOS Boot screen is different from mine. There is a two-way communication between Windows & BIOS using the Firmware Boot Manager ({fwbootmgr}) in the BCD. I'm hoping /RebuildBCD will scan your drives & create a BCD that essentially looks like mine, & then communicate the differences to BIOS. But I begin to wonder whether the task is too great now that I actually see your BIOS Boot screen. But I still do -- kinda mostly -- believe a backup of the BCD should get any damage undone if you could restore it.
(1)
(a) Is the Installation DVD you've got of the same or greater version of Windows that is installed? It would be best if that were the case.
(b)Boot to it, & at its Command Prompt, show a picture of...
DiskPart
List Vol
Exit
=== You should recognize the Windows volume by its label or size ===
=== Note its letter which may not be C: in this environment ===
=== Use that letter instead of X: in the following commands ===
MD X:\BU <<<Make a folder on "C:" named BU
BCDEdit /Export X:\BU\BCD_Backup <<<Backup the BCD into it
BCDEdit <<<Show partial BCD
That's just making the BCD backup, so you won't have to do it later should we decide to proceed.
(2)
(a) Is there more at that BIOS Boot screen, like whether it is in UEFI or Legacy mode or whether CMS is on or off?
(b) What do Boot Options 2 through 4 look like? I wonder whether one of them has an option for {bootmgr} -- just like that.
But I am getting cold feet about this. I'm glad you hesitated.