how to change ip address?

You might get more help if you would learn to write in English rather than that juvenile lingo you used. However, since you seem to be a beginner, I will make an exception to my general rule, and answer your question.

First, you can't change it, only your ISP can. You don't say what kind of connection you have. If it is dial-up, it changes every time you log on. If you are on broadband, it varies with the individual ISP. Some may change it on a periodic basis, some may change it after some period of inactivity, some may change it anytime you disconnect the modem, and some may make it permanent (usually on special request). You could call your ISP on this.

Second, protection against hackers is primarily your responsibility. Use an access point with at least NAT, or even better, a hardware firewall. Even with NAT, install a good software firewall on your system. ZoneAlarm has a free version and is quite good -- better than the one built into XP.

Hope this helps, but next time please post in English or I will ignore it.

Frank

why do you think someone would need your IP-address to hack into your PC? Viruses, trojans and spyware usually come due to some action of yourself (download, click, install). Worms tend to find it out on the run, they just crawl in while you're connected.

A firewall is nice and necessary, but do you use anti-virus and anti-spyware also?

Tell more on your connection, protection and the symptoms of the infection. And, f possible, in English that's at least as good as mine (the level of Frank might be as unobtainable for you as it is for me, but that will be no problem for most members).

Kees