My coworker told me to find files and folders for 'advert.dll' telling me that I should get rid of it if it's on my box. Can I delete this file without affecting anything important? What is it?

If is something called "SpyWare". It can also cause browser hangs and other failures. If you want to do a thorough check and cleanup, download AdAware from http://www.lavasoft.de/aaw/index.html

How can I delete the history from Windows Media Player 7? I'm continually listening to stuff then deleting it if I don't want it. Then theres' listing for things I don't have cluttering up the list.

this really has nothing to do with this particular thread does it? Don't add to an existing thread. Scroll to the bottom of the first page and add your message there. Justin if you read this, that is a dumb place for new messages. There should be and ADD NEW MESSAGE link at the top of the page

A good trick to use with advert.dll is to delete it. Then open Notepad and create an empty text file but name it advert.dll. Then place this file in your C:\Windows\System folder. If advert tries to install itself again it will be fooled into thinking it is already on board and will not install. I think this tip came from Fred Langa but I am not sure.

grc.com's freeware OptOut utility removes advert.dll and a number of other things. http://grc.com/files/optout.exe