Just five min ago my computer restarted when the cisco routers got done reloading.

First it was the 3600 I just got and then it was the 2612. This has never happened before. I am using a serial to usb converter because I don't have any serial ports on this laptop or my desktop and I made sure all the settings were correct to connect to the routers. My serial converter did have trouble with the usb hub on my desktop so i unplugged it and plugged it back in and the usb port does work.
Does anyone have any advice?

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I wasn't sure if this is the right place to post this.