If you're using Toolbars such as a Google or Yahoo toolbar, try uninstalling them.
If that doesn't help, please try downloading, install, updating, then run a full system scan with BOTH of the free malware removal tools from the links below:
SUPERAntispyware Removal Tool
Hope this helps.
When I close a site on the internet i get a message saying "the instruction at "0x42fb1fff" referenced memory at "0x02141efo" the memory could not be read". I see the page with no problems. I have 1gig of memory on this computer, am using windows xp professional. My computer is an Asus..