Windows 7: how often should a full system antivirus scan be run

Just wondering how often a full system antivirus scan be run? only had windows 7 professional for a little over a week now and sure don't want any viruses on it.

Are you running a real time protection scheme?
If so you are for the most part covered, unless you decide to let something through.

I don't think there is really an agreed upon answer to this question. I suppose the best answer would be however often makes you feel safe.

Factors involved too, how much use does the system get, how often are you just randomly surfing around the web in parts unknown.
I would just schedule it for once a week unless I started finding stuff then I might increase the frequency.

Best thing you can do is stay on top of windows update, as they patch a vast majority of the exploits used by the viruses.

I am using comodo internet security premium suite. it updates a couple times a day that i have noticed when i am using the laptop all day otherwise once a day.

Also never hurt to get an external device for pictures and stuff you don't want to lose in the sad event you do get a nasty infection, or something breaks down.

or in the event the laptop gets stolen like my macbook did 2 weeks ago

It's really a very personal preference. Ideally, I think it should be done right after each update, just after getting new virus definitions, and also right after installing anything new. That's the most aggressive option if you're really paranoid.

A more normal option is to do it each night, when you're not using the computer at all, or at any time that you can left it powered on, but not using it. Once a week is also a common suggestion.

But most important of all, you must think what you do with your computer. If you almost never install anything, do little web surfing and work with offline stuff most time, you will not need to check that frequently. But if you're most time getting things from internet, a regular scan is better.