Help with fps problems.

i always played with 100+ fps on the usual. i left the country for a month without my laptop and i barely strike 60 now.

its a brand new laptop that i didnt mess with. i played 2 games on my friends laptop which is a bit older and it has 80+ fps.

what do i do to revert my fps to normal?

i didnt touch it once for a month so is that the problem?

my laptop has this thing where if i take it out of the charge the fps goes to 30 but when i put it back it went to the usual 100+ .

i just tried doing it over and it shows the 120 fps then drops instantly to barely 60.