Microsoft has a vast knowledge base available for all of their products.

For 40 years, Computerworld has been the leading source of technology news and information for IT influencers worldwide. Computerworld's award-winning Web site (Computerworld.com), weekly publication, focused conference series and custom research form the hub of the world's largest global IT media network.

Learn all about how your personal computer works at How Stuff Works.

WhatIs.com® is a knowledge exploration and self-education tool about information technology, especially about the Internet and computers. It contains over 4,500 individual encyclopedic definition/topics, a number of "Fast Reference" pages and learning tools. The topics contain about 12,000 hyperlinked cross-references between definition-topics and to other sites for further information. The site is constantly updated.

Dell provides support and downloads for all of their products through this site.