Helpin' each other is the name of the game, Scarlett
Marginally effective anti-spyware (or anti-malware) programs aren't good, so it's important to have someway to kinda compare 'em. The problems develop in such a way, quickly, that it's best to have a couple anti-malware
apps on your machine so what one doesn't catch this week, the other might. In anti-virus
, a pair 'o them wil probably confict with each other. ( don't ask me why, exactly... but they will. ) The same can hold true for the others, but trial & error on the part of many people can establish that some will work, some won't and that's why there are so few recommended ones at the spywareWarrior link above. There are many in a gray area in-between though. I'll be comfortable with a select few and count on the definition updates
they frequently issue. The on-line scans
prove their value the same way, by sometimes daily re-defining
what's bad. It's good to use them also.