I had that exact same message about two weeks ago it happened because I didn't shut the computer down and fell asleep I woke up and just switched off by holding the power button for a few seconds this is called a hard shutdown and shouldn't cause any problems but this time it did, possibly because the computer was in the middle doing updates at the time.
How I fixed it
I entered the bios set up and looked at the boot priority I have two hard drives but only one was showing and the one showing was not the boot drive so I went into advanced setting where I could see a list of all the drives some of which were not part of the system from here I deleted all the drives apart my boot drive and set it as priority one, exit and save and bobs your uncle.
Also ExtremeNinja even if you don't try to fix it you should still be able to start your laptop by pressing F8 when you hear the beep this will bring up a list of drives and partitions (It only does this when the bootmgr is missing otherwise it brings up a start menu.) use the down arrow key to highlight your boot drive and press enter this won't fix the problem you would have to do this every time you started your lap top.
How I fixed it
I entered the bios set up and looked at the boot priority I have two hard drives but only one was showing and the one showing was not the boot drive so I went into advanced setting where I could see a list of all the drives some of which were not part of the system from here I deleted all the drives apart my boot drive and set it as priority one, exit and save and bobs your uncle.
Also ExtremeNinja even if you don't try to fix it you should still be able to start your laptop by pressing F8 when you hear the beep this will bring up a list of drives and partitions (It only does this when the bootmgr is missing otherwise it brings up a start menu.) use the down arrow key to highlight your boot drive and press enter this won't fix the problem you would have to do this every time you started your lap top.