Desktop will not boot

Gets past the Dell logo screen then when the Intel copyright info. appears at the top of the screen it is followed by this message:

BOOTMGR is missing

Press Ctrl+Alt+Del to restart

Then it just does the same thing when it restarts. Also have the error code 2000-8146 with this message:

Hard Drive 8 - self test log shows previous error

The computer is a little old and was freezing up sometimes so i did a complete factory reset and it helped alot...then it started to have problems so i started another factory reset...but this time it didnt do anything and apprared to have frozen up so i had to manually turn it off and when i turned it back on it would not boot anymore and i got the message listed above. I am SO hoping its something simple and wont cost $ cause i dont have any way to pay for any repairs or parts or whatever...i dont even have food for my dog right now im really hurting...and i use the computer to make what little $i can - so without it i am REALLY screwed!! PLEASE HELP. Thank you so much. :-)