What causes my computer to lock up every time I start internet explorer of Outlook?

I have a Dell Computer that just started to freeze each time I open Internet Explore of Outlook. I did a scan using Norton Antivirus and nothing was detected.

What causes my computer to lock up every time I start internet explorer of Outlook?hijackthis

could be program running in background like updates/etc.could be scanning e mails coming in,run scan disk look for errors,run windows registry tool scan these helped me in the past.

What causes my computer to lock up every time I start internet explorer of Outlook?malware

Recommend you to use firefox browser. It can prevent virus such as worm,trojan etc.The newest official edition of firefox can be downloaded from http://www.mollzia.com