Malware in the disguise of an antivirus..................................

Yesterday i had the worst of all experiences of using an antivirus. Doesn't that sound odd ......yes, it does. All of  a sudden my PC slowed down, which made me go insane. AArrgh!!  I tried every  means to fix it but for vain.  Even system restore didn't work. Almost every program stuck with a common error message **Not Responding** . At the moment i could not figure out the exact cause, using registry error fixers repeatedly made it even worse.  At last! it came my mind that it could be the affect of an anti-virus that i had installed  a day ago. That was Eset NOD32 Anti-virus, quickly i opened the control panel to uninstall it, but to my astonishment remove option was missing. This made me quite sure that it was because of the stuff only that my comp. was malfunctioning. After that i Googled for the uninstaller a got one downloaded from its company forum. Thereafter, i uninstalled the program and my computer was the same as before.
I'm not personally criticizing a product but sharing my experience, i'm not quite sure about how it works on other computers. It may be working well on other computers. Anybody having similiar experience may leave a comment.