When i checked my processes running in the computer, igfxpers.exe and igfxtay.exe are also running? What are these what are their conseqeunces?

You can look up process's here.
ProcessLibrary.com - The online resource for process information! (there are others if you search)

The ones you asked about are software for your processor, or graphics card (intel). Best for you just to leave them.
igfxtray.exe - What is igfxtray.exe?
igfxpers.exe - What is igfxpers.exe?