Feedback, Complaints or Problems

i used for my OS of the Eset smart security and was good for me,
i decide change my anti virus to the kaspersky internet security,and my trouble beginning!!!
i remove the Eset smart security by strongest uninstaller software and started instal kaspersky but showed error for me!!that, eset smart security not allow to you for instal new antivirus!!! i did everything that i know!!
clear history,again instal ESET and remove again, next, restart my OS,never!!never,never!!
show me again that error!!!!!
i am nerves because i obliged to change my OS again