Fps drop dramatically after reinstall windows

[bvnchanin]

Hello,
MY fps recently droped in CSGO from 250-300 constant to around 50-80 after I changed the number of processor in msconfig from 2 to 1.

I went to msconfig and did stupid which was changing the processor number from 2 to 1 without knowing what it will do. Later on I found out that my fps drops down dramatically, I tried reinstalling windows and changing the number back to the original amount but the problem still occurs.

How can I get my fps back to what I used to have?

specs
Intel i7-2600 CPU@ 3.4Ghz
6GB RAM
GeForce GTX 660 Ti

Previously i was using windows 10 but now using windows8 which i dont think is the main reason for a 200fps lost.

I went to nvidia control to make sure that everything is set at the correct setting already.
I cleaned off dust very often and my cpu is running normal.

 

[hang-the-9]

So you did not just change the msconfig setting you also changed Windows versions. When you re-installed Windows did you install the graphics drivers and motherboard drivers? Try resetting the BIOS to defaults? Is the video cable in the nVidia card and not the motherboard video?