Another Server

This morning I was upgrading my web server to F16. It came time to reboot, and now it won’t boot. Powers up, though. I went an bought a PSU tester, seems I will need one, now that I’m back to being a HW guy. I’ll guess PSU, CPU, or Motherboard is the issue. For the first time in years, www.techharbor.com is DOWN

What happened to bring this computer misery on me?