mfa head scratch

hi all as i have been scratching my head a few times lately with electrical gremlins as people seem to call them, i seem to have the problem that my mfa isnt working ive done the fuse pull for 30 seconds .it used to work up to the cold spell we got over xmas where a frost plug also blew .when i started the car yesterday the digital clock showed something for 2 -3 seconds then gone ,battery was low had to jump start what do ye think the problem could be anyone experience the same problem