My web pages used to auto login to dvinfo.net and dvxuser.com and some others as well. Now when I close internet exlorer and reopen it, I have to log into all my discussion forums again.

What could be the problem?

Sounds like a cookie problem (cookies are text files Web sites can write to your hard drive to store things like site passwords or other information). Open Internet Explorer, and go to Tools>Internet Options and click the Privacy tab. Click on Sites, and then enter the address of the Web site you want to allow cookies for (such as dvinfo.net). Click on "Allow". Repeat for any other sites you wish to allow cookies for.

EDIT: Have you by chance recently installed a firewall like ZoneAlarm Pro? A firewall like this one can block features like cookies.

Personally, simply from a security standpoint I would encourage you to switch to another browser such as Netscape (http://browser.netscape.com/ns8/) or Firefox (www.mozilla.com). Both are more secure than Internet Explorer.