Netscape disabled

I often find that Netscape has stopped working. On the web screeen it appears to be contacting the website but nothing happens; on the email screen clicking Get Messages has no effect – except that the Get Messages logo goes in and out. The problem can be solved by clsoing Netscape using TaskMgr and then restarting Netscape. This seems to be happening more frequently since I updated Windows XP with SP2. How can I get continuous working?