Hello dear sir,
I presume you are new here. Plase take a few minutes to read the forum rules here: http://www.tomshardware.com/forum/19-73-forum-rules-read-first
Your problem could be cause by many things: overheating, virus, bad components.
first open you computer box and clean dust.
second, boot in safe mode with networking and try to scan for viruses with roguekiller, adwcleaner, malwarebyte anti-malware, tdsskiller,
If all clean, you might want to download temperature monitoring such as coretemp, speedfan, hwmonitor to check you temps
What are your computer specs ?