IE6.0 often slow to open webpages, works fine at other times

[xpnewbie58]

Everything's been working fine but recently IE6.0 has been opening some webpages slowly, many of which time out without opening the page at all. At other times those same webpages will snap right open like they used to. The slow opening of pages does not seem to be occurring only at certain time of the day. I can't figure out what it might be that I'm doing that causes it to start opening pages slowly (or not at all). Everything's always worked fine in the past. I have broadband connection, WinXP Home , IE6.0, all Windows Updates except SP2, ZoneAlarm, Norton SystemWorks 2004. Everything works flawlessly and always has until this problem started a week or so ago. I have run virus scans in Norton AV and have also done scans in AdAware and Spybot with most recent definitions and everything checks out fine with those. ANY SUGGESTIONS WOULD BE MUCH APPRECIATED !!!