RAM memory slots not working !!!

After replacing the paste on the processor, the RAM slots do not work.
I had 4 busy, at the moment I have 1 and 3 busy, I put the memory in slots 2 and 4.
It causes that the computer does not start and after a few seconds, reset itself.
Can I fix it somehow?

Reset the RAM modules by reconnecting the RAM modules.
Blow off any loose dust or debris from the RAM using canned air. Hold the module by its edges.
Clean the contacts using a soft cloth that does not leave fibers behind, such as a lens cleaning cloth slightly moistened with rubbing alcohol.

Did you remove the CPU to replace the thermal paste?

If so, I hope that you didn't damage any of the contacts in the LGA (land grid array). The memory controller is typically integrated with the CPU with current processors, so damaging the CPU or its socket can lead to RAM not working.

I did something like that last year, with an AMD CPU. (Tore it out of its socket due to a thermal compound that was more adhesive than I was accustomed to.) Destroyed the CPU and damaged the motherboard when I re-inserted it. It was an expensive lesson.

Ghot said:

If you used a bit too much thermal compound, it could have leaked out the sides, and affected the pins of the CPU.
Either shorting them, or insulating them from making contact.
THIS could affect the RAM slots.

In fact I had it happen to me once, with non-conducting thermal compound.
Once I cleaned it out of the CPU socket...everything worked again.

That would have been nicer than damaging the LGA socket.

Cleaning thermal compound out of that socket would have to be done extremely carefully. The fingers that engage the LGA pads on the CPU are probably rather fragile.