Official Microsoft support site with Knowledgebase articles for troubleshooting Windows and other Microsoft products.
» Windows Sysinternals
For utilities such as Autoruns, Process Explorer, Process Monitor and troubleshooting blog by Mark Russinovich.
» Microsoft TechNet
Another Microsoft support site with with in-depth articles for IT Professionals.
» Majorgeeks Excellent download site for drivers, freeware, shareware and anti-virus / anti-spyware tools.
Resources and articles for Computer Technicians