Each time your computer announces that is going to restart, click Start -> Run, and type shutdown -a. This will abort the shutdown. Then go to Start -> Control Panel -> Administrative Tools -> Services. Find "Remote Procedure Call (RPC)" and double-click it. On the Recovery Tab, choose "Take No Action" for the first three options, and then click OK. This will stop your computer from restarting when RPC goes down, so at least you'll have time to fix the problem. Once you think the problem is fixed, make sure you change those three back to "Restart the Computer."