When I go to Putfile, or certain other video sites, I get the page, but the video area just says that I need a plug-in to watch the video. When I click on the "Install plug-in" link it tells me it can't find the right plug-in. How do I solve this?

usually you can reinstall the main program. So if it is a windows media video that is getting the error, reinstall Windows Media Player. I had this same problem.

i had some similar trouble with Firefox with Macromedia Flash, i had to go to the web site and manually install it on my own..

Yes, but which plugin do I need?