Something is better than nothing. So if you have to money to buy a paid anti-virus then its better to use the free Anti-Virus from Microsoft. And Microsoft recently upgraded their MSE or Microsoft security essential to version 184.108.40.206.
MSE is one of the simple user friendly anti-virus. Though its does not came in Top 10 Anti-Virus list but its still better to using nothing. If you are using MSE then its time to upgrade it now to get more security on your PC. As Microsoft upgraded it with lots real time protection against Trojan , spyware and other malicious activity. If you are using nothing then grab its free copy and install now. MSE supports Windows XP, Vista and 7 both 32bit and 64bit PC. Free Download Microsoft Security Essential 220.127.116.11 here