I'm a Windows sysadmin. I've been doing this professionally since mid 2008, went to a crappy tech school for 2 years prior to that (I'm not going to dignify them with a link). Almost all of what I know comes from on the job experience and Google searching.
I have experience with enterprise backup software, MSFT Exchange, and I like to think I have pretty good general troubleshooting skills. I'll be the first to admit I don't know everything, but I'll try to be as helpful as possible.
Q&A for professional system and network administrators
Q&A for computer enthusiasts and power users
Stack Exchange Network staging zone, where users come together to build new Q&A sites
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Q&A for Information security professionals
Q&A for professional and enthusiast programmers
Q&A for professional and amateur chefs
Q&A for linguists, etymologists, and serious English language enthusiasts
Q&A for science fiction and fantasy enthusiasts
Q&A for passionate videogamers on all platforms
Q&A for apps, scripts, and development with the Stack Exchange API
Q&A for database professionals who wish to improve their database skills and learn from others in the community
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
Q&A for people who want to be financially literate
Q&A for dedicated home brewers and serious enthusiasts
Q&A for physical fitness professionals, athletes, trainers, and those providing health-related needs