This is a really good and useful site. I like how you put the content first and made it easily accessible. You have good information and lots of it, you definitely built this site for a specific purpose and maintained that scope through the project.
That said, I'd love to see more images with the tips and problems, especially for some of the more advanced items. For instance, in one tip, you recommend the user to use the Superfetch feature in Vista. I think it would be great if you had some screenshots to go along with this. That way, the user could make sure that they are doing everything correctly.
I'd also like to see you make all the text on the website display the same way. I really like the style you used on the change AGP Aperature page. It was easy to read and it was clear.
One more thing I think you could take advantage of is to have people submit problems and fixes too. You could have a little text at the end say something like "Have a better solution? Post it here." In any case, I think there is a good possibility for turning it into a good community site.
In the end, you have good information, and as long as you continue to update it, it will be great.