Cpu dead?? Mobo dead?? All dead??

Hello

Lately, my pc had high temperature problems, obviously caused by lot of dust, stored on the cpu cooling system.
So I decided to clean the mess!
I removed the cpu cooling system, the cpu, cleaned everything, and put them back together. I have done this many times, but this time I forgot to apply thermal paste, on the cpu surface.
After the power on, I got only fan activity, no beeps and black screen only.
I checked the cpu on another pc and it appeared to be dead.

I would like to know: Is there any chance for other parts(mobo, vga card, memories) to have been damaged?

Also, I have a spare cpu, little slower than the previous, same socket although. Is there any danger to damage the spare cpu, if the mobo is already damaged?

Thank you in advance.