How to secure laptop from internal threats like virus and errors

My laptop is good and is working pretty well since i have purchase. The laptop i am using is Dell Insipiron 5520 and from the past week it has been continously suffering from internal bugs and errors. i want to know that how to make it secure from internal threats. please help me as soon as possible.

Hello friend,
Some good antiviruses installation to your PC can fix the problem of bugs and errors such as :-

Avira, AVAST, AVG, Microsoft Security Essentials, Norton Antivirus etc..
any of the above antivirus would serve the job.