Its not really simple to see if anyone has hacked into your computer for personal info until it is too late, check to see if any files have been moved or changed which you havent changed yourself, most hackers defend themself well and the only way to stop them is to have a firewall. I carnt stress this enough, you must have a firewall install if you are connected to the internet in any way.
The best around is ZoneAlarm. Its free and really simple to use, search on google for it.
Simon, June 2006
