What model computer is it? What operating system is it running? What's the name of the missing DLL?

The most common cause of problems like this is spyware/malware. See  ChrisRLG's pinned post in the Virus Information and Removal board for advice.

Jim

Thanks, I've added spybot. My computer is 4300 dell  the dll file APWTIL 

A Google search for APWTIL produced no hits. That's very unusual. Are you certain that's the correct spelling of the missing DLL?

Jim

Thanks Jim,

     That's correct. When i do a search on my computer of files it says that it has something to do with my norton antivirus. I've done the search with the file error right there because I thought I may have misspelled it also.

Strange...Google's usually pretty good at finding common, or even uncommon DLLs!

You may want to try uninstalling/reinstalling Norton Antivirus. I don't use that product, so if you need specific advice on how to do that, post back.

Did scanning the machine with Spybot improve things? Sometimes AdAware will detect things that Spybot doesn't (and vice versa!). Did you try all of ChrisRLG's suggestions?

Jim