Whenever I switch on my PC, it makes some loud sounds till it completely ends the entire booting process, but this sound gets even worse when it’s the winter season and during early mornings.

I am not sure of what type of noises are emanating from the PC, but all I can think of is the noise from the internal fans. The noises can be possibly coming from the power supply fans, cabinet fans or the processor cooling fan. Open the computer case power on the PC. 

Locate the noisy area and pinpoint the exact fan which is making the sounds. Now turn off the PC and remove/disconnect that fan. If it is the power supply fan, disconnect and remove the power supply unit and open it carefully. 

Be careful as the power supply unit deals with high power voltages and can even injure you when it is powered off. This is because the large capacitors inside the PSU still retain high voltages for a while. Let the power supply unit lie for around 15 minutes before you open it. You should then clean the fans thoroughly using a brush and a blower. 

If the fans are still making noise after cleaning, you could remove the fans, dismantle the fan blades and add a few drops of machine oil on the shafts and between the magnet and coil assembly. But this practice is usually not recommended as the fans will work only for a few days or weeks and the problem will arise again. You should replace the fans with the right specifications to be safe. 

The noises could be coming from the power supply fans, cabinet fans or the processor cooling fan.