white boxes with red x's

I can't see any images or pics. Instead there are white boxes with red x's in the middle.

Why?

How do I fix this?

I have Win XP Media Center. PC Tools firewall.

 

Try this: Control Panel > Internet Options > click the Advanced Tab > click Restore Defaults. If that doesn't work, click the Programs Tab > Reset Web Settings. If that doesn't work, take a look here http://support.microsoft.com/kb/283807/en-us
NOTE: this is for Internet Explorer 6; things may be different for IE7. The link has info for both 6 & 7. Alternatively, try a different browser, Firefox and Opera are well known and very popular; personally, I have stopped using IE as of 6 months ago on my home PC....