Does running two antivirus on my computer slow it down?

my computer which operates with vista has two antivirus: kaspersky 6.0 and nod32 3.0 running can these affect the performance of my computer?

Does running two antivirus on my computer slow it down?virus removal

yes, they may conflict with each other and slow down your sysyem. I use AVG free, and have no problems.

Does running two antivirus on my computer slow it down?anti virus protection

yes it will slow down because they will start conflicting. Remove both of them and install avg free.
Both programs are going to use a set amount of resources, that's a given. The bigger issue might be in the fact that they will both try to scan new files as they are created/saved at the same time. This could cause both of them to use more resources and therefore slow you down. Also, if they both find a virus at the same time, you may run into a looping issue.

You could continue to run them both, but I would consider turning off the real-time protection on one of them. If you need to run a scan, you can still use it.
Antivirus software is viewed as a virus by other antivirus software. Having two will will cause conflicts and performance issues. It is possible that one will quarantine the other.

IMHO, you should keep kaspersky over nod32, simply because the viral definitions are updated sooner. This will allow you to keep using one of the av's you already have, rather than taking them both off and installing another free one that you may not be used to.
As everyone agrees, you shouldn't run two antivirus because they will conflict.