Partition is there, but Windows boot option is gone?

Question

Hey folks, I'm having a small issue with bootcamp.
Not too long ago did I have Windows running just fine on my Mac; everything was up to date, I managed to install 7 and upgrade to 8.1 just fine. Everything was good until one evening I open my Mac up, there is a command line that states "no bootable device." I don't believe I had installed Yosemite because last time I shut the Mac it was in Windows. I found a thread from another user here, and followed LonerT's suggestions and managed to get Windows back as a boot option, but the command line still pops up with "non-system disk."
The bootcamp partition is still on my HD with everything installed, so if there's some way I could get this back to how it was without having to go through the hassle of erasing the partition and starting anew I would be greatly appreciative.
Thanks!

Answer 1

Whoa, LonerT!?
Certainly, here are the results of the commands:
joshuas-mbp:~ joshua$ diskutil list
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            394.4 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data MAC TO PC               5.0 GB     disk0s4
   5:       Microsoft Basic Data BOOTCAMP                100.0 GB   disk0s5
joshuas-mbp:~ joshua$
joshuas-mbp:~ joshua$ diskutil cs list
No CoreStorage logical volume groups found
joshuas-mbp:~ joshua$
joshuas-mbp:~ joshua$ sudo gpt -vv -r show /dev/disk0
Password:
gpt show: /dev/disk0: mediasize=500277790720; sectorsize=512; blocks=977105060
gpt show: /dev/disk0: Suspicious MBR at sector 0
gpt show: /dev/disk0: Pri GPT at sector 1
gpt show: /dev/disk0: Sec GPT at sector 977105059
      start       size  index  contents
          0          1         MBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34          6       
         40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
     409640  770347720      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  770757360    1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  772026896       1520       
  772028416    9762816      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  781791232       2048       
  781793280  195311616      5  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  977104896        131       
  977105027         32         Sec GPT table
  977105059          1         Sec GPT header
joshuas-mbp:~ joshua$
joshuas-mbp:~ joshua$ sudo fdisk /dev/disk0
Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]
Signature: 0xAA55
         Starting       Ending
#: id  cyl  hd sec -  cyl  hd sec [     start -       size]
1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>
2: AF 1023 254  63 - 1023 254  63 [    409640 -  770347720] HFS+      
3: AB 1023 254  63 - 1023 254  63 [ 770757360 -    1269536] Darwin Boot
*4: 07 1023 254  63 - 1023 254  63 [ 772028416 -    9762816] HPFS/QNX/AUX
joshuas-mbp:~ joshua$
I thought the corestorage command was a bit odd so I looked around the web to find out what it means. It doesn't sound promising.
As for you question on "what modifications were made to get [the drive] bootable again:"
I followed these instructions you gave in that thread listed above...
Here is an example.
sudo fdisk -e /dev/disk0
Password:
fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory
Enter 'help' for information
fdisk: 1> p
Disk: /dev/disk0 geometry: 121643/255/63 [1954210120 sectors]
Offset: 0 Signature: 0xAA55
         Starting       Ending
#: id  cyl  hd sec -  cyl  hd sec [     start -       size]
1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>
2: AF 1023 254  63 - 1023 254  63 [    409640 - 1452530904] HFS+      
3: AB 1023 254  63 - 1023 254  63 [1452940544 -    1269536] Darwin Boot
*4: 07 1023 254  63 - 1023 254  63 [1454211072 -  499998720] HPFS/QNX/AUX
fdisk: 1> setpid 4
         Starting       Ending
#: id  cyl  hd sec -  cyl  hd sec [     start -       size]
*4: 07 1023 254  63 - 1023 254  63 [1454211072 -  499998720] HPFS/QNX/AUX
Partition id ('0' to disable)  [0 - FF]: [7] (? for help)
fdisk: 1> flag 4
Partition 4 marked active.
Saying the Windows is bootable may be a bit subjective; the option appeared after this example you gave, but it won't boot into Windows.