Mercedes C-Class will not start, everything lights up but car will not start when key is turned in ignition

hi there! i have a 2002 c230 kompressor coupe that will not start. when i
turn the key i hear the fuel pump whirring up but the car will not start. i also
noticed that on the display where "W" or "S" should be its not showing
either one. sometimes when i pull the battery (battery is a year old and has
a perfect charge) and reset the car it'll show the "W" or "S" and then the car
will start. there was a time when i drove it and it went into limp mode and
the speedometer wasnt working as well as an error on my screen saying
"display malfunction - visit workshop". i thought this was an error with the
lcd screen as part of it wasnt working anymore so it has a brand new one
installed. any thoughts or related problems anyone?