Question i have just got my laptop screen replaced to a new in a IT store but my cpu usage is at 100%

[mubasi]

the laptop is acer aspire e5 575g
specs:
i5-7200u
gtx940mx and intel hd graphics 620
8gb ram
240 gb ssd

i just got my screen replaced fixed and i was so happy that i got my laptop back, but when i opened the resolution was smaller and it was lagging also one the screen froze.
when i restarted it the fan began to make high noise and the cpu usage was at 100% and i dont know what to do.
the battery is only lasting 2 hours now before was 4 hours
is it the screen that done that or another problem on the laptop

 

[cin19]

I think you should go back the same IT store, let them fix for you again. Or try other store.