Hi macuser,
Spybot search and destroy does have a restart feature yes. I am pretty sure this can be disabled though. I haven't used the program myself in quite some time though.
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It should be noted that (at least when I used to use it) it was somewhat CPU intensive depending on your CPU. I believe there is a guide on Spybot forums on how to make it not quite as intensive but I am not allowed to link the site.
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One last option is to try something like this
Right click on My Computer, click properties, click on the advanced tab, click on settings, under System Failure uncheck the option....Automatically Restart.
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I am not affiliated with Best Buy nor have I ever been employed by Best Buy. All of my thoughts and posts are of my own opinion and personal experience.
I may not always know the right answer, but I will always tell you what I do know. I also do free computer analysis and consultation via private message.