I need help with my pc

[Biscuit Sensei]

I bought a laptop in August 2014. It has an intel core i74700mq 2.4GHz, 8GB RAM and an Nvidia GT840m. When I got my laptop it was able to play games such as Arma 2 Dayz Mod on low settings at around 25-30 fps and games such as battlefield 3 at low settings at around 30-40 fps. However now when I play those games they are unplayable at around 7 fps on the same settings as they were before. Is there any solution to this problem?

 

[Bossyfins]

Have you cleaned your PC out? Have you run an AntiVirus/AntiMalware program?

 

[Biscuit Sensei]

Have you cleaned your PC out? Have you run an AntiVirus/AntiMalware program?

I have done that with McAfee antivirus

 

[Bossyfins]

Have you dusted your PC out?