security downloads

[dummie]

For a while I have been reading and receiving advice on various progs to help security and only yesterday I was directed to the link below..
http://www.spychecker.com/ which looks very good .

My question is...where /when do you stop installing security progs because (A) they all sound very similar and (B) surely the more you have, the bigger chance that pc will start getting choked up.

How does a relative inexperienced user decide which/how many etc.

I have at present..diskclean/scandisk/spybot/regseeker/enditall/mailwasher/ and I use them all daily???????????

[Restek]