Router - enough protection?

[jfcarbel]

Can a hacker gain access to my computer thru an port that is forwarded on my Router for a P2P app even if the app is not running?

[colordog]

Sure.

If the port is being forwarded, it's being forwarded whether you have the app open or not.

[jfcarbel]

So anyone using a P2P program cannot protect themselves?

Is there anything I can do to prevent hackers from getting in?

[colordog]

Install a firewall that monitors the port.

Close the port if you're not using your application.

Don't use the application.

Remember, just because you have a port open doesn't necessarily mean that you're wide open to attack. With an open port, either something installed needs to be listening, or there needs to be an exploitable vulnerability of the port, protocol, etc.

[Sirber]

don't be paranoid about hackers, no one want to break you :)

[The Belgain]

I'm with Sirber on this one. Assuming you aren't the CEO of some company, or working in a government, bank, etc... there is no reason why anyone would particularly want to break into your computer (as long as you don't spend your time pissing off script-kiddies on IRC).

The thing to be more worried about is viruses, which are indiscriminate by nature and will attack any vulnerable computer. So just make sure you have a decent upto date virus scanner.