Is this bad???

[FlyRealHigh]

My pc isn’t working and I’m not sure if it’s the cpu or motherboard that’s the problem. Opened the cpu cooler and found this. Any advice?

[ARandomPerson]

That seems like dried out thermal paste. Not good but all you have to do is clean off the paste with some cleaning alcohol and coffee filters and apply some thermal paste. After you reinstall the cooler and boot it back up again, I would recommend stress testing the CPU to see if your application of thermal paste was correct. 

[TatamiMatt]

8 minutes ago, FlyRealHigh said:

My pc isn’t working and I’m not sure if it’s the cpu or motherboard that’s the problem. Opened the cpu cooler and found this. Any advice?

Remember to also reattach cooler using opposite diagonals and making sure all pins are entirely though the motherboard to ensure even and adequate pressure

[Needfuldoer]

That's just what old thermal paste does. It's sub-optimal for cooling, but wouldn't cause a no-POST by itself.

 

Clean it off and apply some fresh thermal paste before you put the cooler back on.

[AlfaProto]

7 hours ago, FlyRealHigh said:

My pc isn’t working and I’m not sure if it’s the cpu or motherboard that’s the problem. Opened the cpu cooler and found this. Any advice?

It's probably the board.

 

Even if the paste is dried to a crust, it will still be able to post, boot to Windows with poor thermals.