Question CPU turns on but no display

Mar 16, 2019
I have a custom built pc having intel DH67CL motherboard and intel core i5 2400 processor. Recently, my PSU went bad and i had to replace it. I have an external radeon GPU. The CPU appeared to run fine on the replaced PSUand i tested it by playing some high end games. However, after replacing the faulty PSU, i noticed that there is a loud sound of fan that was not there before the replacement of the PSU. The sound of the fan became even louder when i started to play a game which led me to assume that the sound is being generated by the GPU fan, rather the PSU fan. To confirm this, i decided to remove the GPU and see if the sound still persists. However, after removing the GPU, i encountered a new problem. The PC would not provide any display upon powering up. All the fans start to run and the led on motherboard indicating power also lits up, but without display. Also, there is no HDD activity. Initially i thought that it may be related to RAM, so i removed the RAM and re connected it but to no use. Another strange thing was that there was no beep from cpu motherboard when i powered it on with the RAM completely removed.
Please help