it could be any where to 30 seconds to 10 minutes or more depending what you run. when i have almoast all of the roles installed including domain Controller with roaming profiles, it takes about 2 - 4 mins. that incudes saving settings and loging off. if you have schema additives such as exchange server 2003 enterprise edition. it can take 15 minutes or more. if you could describe the server software and the workload that you computer in under I could probably tell you. The fastest way to do it is just to try it. Get at stop watch, time it and then add 5 minutes to the "critical time" that you need. also tell me what drives your running and other devices that draw lots of power this could help me to understand your situation much better.