i think they meant psu,power supply unit .
also a good time for a ram scan ,download memtest86 iso and burn to disk ,boot computer to disk and rum ram test for about 6-8 hrs or even over night
http://www.memtest86.com/memtest86-3.4a.iso.zip
use isobuster to burn the memtest iso,if you don't have burning software that will burn iso's
http://www.isobuster.com/isobusterdownload.php