Shahzad

I wouldn't expalin the results of mistakes in your circuit since my friends have already done that. Instead, I will focus on modifications in your existing circuit.

1) Do you or your friend know the purpose of the 1K resistor in the ground lead of 7812? I am sure, you people don't. Remove this and connect middle pin of 7812 directly to ground.

2) Remove both 1N4148. Directly connect 7812's o/p to the i/p of 7805.

3) Add 1000uF/35V capacitor at the i/p of 7812

4) Add 470uF/25V capacitor at the o/p of 7812

5) Add 220uF/16V at the o/p of 7805.

6) Don't remove the 100nF capacitors at the o/p of both regulators.

The values of these capacitors are dependent upon the anount of load, which you did not mention yet.

Giving the schematic to people for calculating load is not good. You should get an ammeter and measure the max. load of you circuit, yourself.