local hard drive problem

hi
i have 2 hard disk. 1 c and 1 d. d is working fine but c:\ always whenever i close the computer or wait for 5 min or so, these files keep on coming up and take all my space left. i delete them and then they just come back. they are called kazaa, kazaa lite, shareaza, gnucleus. edonkey2000, emule, warez p2p network, etc.
how can i permamently delete them?
plz help
thanks