Posted 19 May 2009 - 09:40 AM
If you mean is it advisable to have two AV applications simultaneously providing real-time protection, then the accepted answer is no; both chugging along can interfere with one another causing conflicts, and can slow down your computer. It is possible, however, to have two on your computer's hard drive, with only one at a time providing real time protection; however, one must be on constant guard because often the "live" application will detect the other's virus definitions and propose to delete them. Lastly, the additional coverage provided by a second AV is not as wide as with anti-spyware applications where the variety of criteria is greater.
Whereof one cannot speak, thereof one should be silent.