For a quick solution you can close all unwanted applications running in background. you can do it by
1. search for msconfig.exe in os installation drive.(alternatively go to run and type msconfig and hit enter)
2. run it
3. go to start up tab and disable all unwanted programs.()do not disable antivirus program
4. save and restart
If you can throw in some money I would recommend you to go for a new pc as most parts needed for you motherboard would not be available. You can buy a whole system in less than $200(without moniter)