Unable to Install any antivirus in my system?

[jack]

I am experiencing a weird problem.Till a few days back i was using AVAST antivirus in my system.Owing to some problems, i decided to uninstall it and go for Kaspersky anti virus.I uninstall ed AVAST and downloaded free version of Kaspersky in my system...The problem is that when i am running the software to install it in my system,the software installation process is not getting completed....(the dialogue box that guides through the installation process disappears midway and no shortcut icon is crated in the desktop) .Having tried to install kaspersky for a few times, i decided to give up and try Quickheal...However the same problem continued....Now i am running my system without any anti virus.Can somebody tell what is the problem and how to solve it out....