Dont know if I've killed my pc

[Ballsdeep]

I took off the CPU fan to see if it needed new thermal paste, i dont know if that made my pc all of a sudden have bad fps and

 

[Hazle]

if you didn't clean off the old paste & re-apply a new one, then yes, your CPU is likely heating up & throttling it's performance.

 

[Ballsdeep]

I need to reapply thermal paste but my pc only dropped in performance since i took off the fan, does that happen?

 

[Hazle]

you need to elaborate further here as you're not being totally clear; is the cpu heatsink+fan properly mounted? did you remove the old paste & re-apply a new paste?

the CPU NEEDS the heatsink & fan to cool properly (or requires a large quality heatsink + enough airflow through the case if you're doing passive). simply removing a heatsink without re-applying the thermal paste will introduce gaps or bubbles on the old paste, & WILL result in higher temps.