I installed some new software onto the server which got on fine, but there was ONE file that happened to be corrupted or perhaps infected and as soon as someome executed that file, the whole of the office's computers stood still because the server had crashed.
We got it back up, but it wasn't even 5 minutes before it went again. The problem seamed to be easing up as it didnt happen agen that day or the next, but then it crashed again. I fixed it, the next day it crashed again. Somedays you get through a day without a server crash. It really is becoming a pain.
I'm currently running anti-viral software on there now to see if it picks up anything suspicious, any ideas as to what could be causing this.