Reset computer after charge/change batt?
 

I just bought a 2000 C240 elegance AT (old shape). The car stood for 3 months and the battery is flat ( can be jump started ). I want to charge the battery -
must i disconnect the cables? If I disconnect the cables to charge or swap the battery if not able to take a charge, will I have to have the computer reset at a MB shop?
My friend told me that all the settings of the computer will be wrong because the battery went dead. Is this true.
My 1st Merc. total noob.

i'm not familiar with your particular model, but for the 2000 E320 and the 1999
E320, I simply 'resync' the seats (cycle full fwd/full back), windows (close, hold
button close for 3 secs..each window), roof (full close, hold 3 secs), and radio
(enter security #) myself.

p.s. 99 has been recharged several times. i did not disconnect any instance.
i've not had to recharge the 00, which has more electronic demands. i've
read caveat NOT TO INSERT ignition key in ignition during charging....but
unknown the foundation.