I was just wondering how long it had been since I reset my computer (which I tend to do rarely if I can possibly avoid it) and remembered that at some point I had a simple command line utility that would tell you exactly that. After a quick search I found Uptime.exe over on the ancient Windows NT 4.0 server page.
\\MUTANTFROG has been up for: 8 day(s), 11 hour(s), 57 minute(s), 6 second(s)