2 anti virus?

is it ok to have 2 anti virus? i heard that we should not have 2 anti virus coz it could clash or something…and is it SPYWARE DOCTOR WITH ANTIVIRUS is consider as antivirus?? i had it installed and i also have panda in my pc..
Answer #1
It makes no sense to have 2. They just eat up resources together.
Answer #2
so spyware doctor is consider as antivirus?
Answer #3
Yes it is antispy and antivirus in one package. You could get some antispy alone.