-Your video driver is acting up. Updating the driver for your video card or chip may solve the problem.
Also, if your PC is connected to a router by way of an Ethernet connection, update the driver for your Ethernet card.

-You have browser add-ons. Utilities or programs added to your browser to supposedly make your online experience better - a search toolbar, for example - can lead to freezes.
If you have any such utilities, or even if you are not sure, disable browser add-ons.

-You donâ€@trade;t allocate enough space to Temporary Internet files. In Internet Explorer, go to Tools/Internet Options. In the Temporary Internet Files section, click on the Settings button. Move the slider in 'Amount of disk space to use' a notch or two to the right.If you are using another browser the instructions could be different.

-Your Temporary Internet Files folder is overloaded. This is not necessarily a contradiction to what was suggested above.
Empty the Temporary Internet Files folder after every online session.

-Your browser is out of date. Upgrade to the latest version of Internet Explorer, Netscape,Firefox or whatever browser you want.

-There is a problem with your Internet security program. Turn off your firewall and antivirus programs, then try to go online. If the computer does not freeze, you found the answer.

-Microsoft says that if you are using McAfee VirusScan 4.02 or 4.03 in conjunction with Internet Explorer 5, your computer may choke online.
McAfee has posted a workaround, though the much better solution is to upgrade Internet Explorer and McAfee. The title on the workaround article deals with Outlook Express, but it is relevant to these types of freezes as well.

-You use Symantecâ€@trade;s Smart Sweep/Internet Sweep. Symantec says its Smart Sweep/Internet Sweep utility, which monitors the installation of new programs including Internet-related programs such as ActiveX controls, can cause Internet freezes if Sweep conflicts with another program.
Symantec recommends you stop Sweep from loading automatically and start it manually.

-Hardware acceleration is set too high. Windows has a Graphics Hardware Accelerator utility. It moves graphics information to the video card quickly.
But if the card cannot handle a fast stream, freezes and other problems can ensue.

-You are using a dial-up connection and have Call Waiting. Configure your modem to disable Call Waiting while you are online. In the Control Panel, click on Modems and look around for the enable/disable option.

-Your PC has been infiltrated by spyware or other sorts of malware. Get your hands on some anti-malware software and have it scour your PC for intruders. Spybot and Ad-Aware are good programs to consider.

Source: philly.com