A little more information about your computer brand name and the type of internet connection you're using would help.
Have you installed all the Vista related Windows Updates including the reliability updates?
http://www.microsoft.com/downloads/results.aspx?DisplayLang=en&nr=20&freetext=vista+%2breliability&sortCriteria=popularity
Have you tried a different browser such as the free Firefox? (Does it continue with Firefox which can be downloaded from the link below:
http://www.mozilla.com/firefox/
Tired installing an updated ethernet driver? (or wireless driver if you're using a wireless connection)
Does temporarily disabling your firewall help the situation?
Hope this helps and let us know more.
Grif
Vista Home Premium
After being on the Internet for an extended period time or opening multiple pages or tabs IE basically freezes and will allow nothing more to occur. Has anyone else had this problem?
Thanks for any help.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic