asteko

It doesn't pop-up. As I said before, I have to dial-up (no matter if it's connected to phone line or not) to prevent my computer to restart.

Thanks for the response. My browser is Firefox (then Phoenix) for the last two years. I also use Ad-aware, Spybot - Search & Destroy, Norton Antivirus, and ZoneAlarm. All are up to date. I scan my system regularly and it's very clean. One thing I want to mention again that I click on a dial-up connection to prevent PC from restarting. It's not done by the computer itself. When I don't do this, it restarts instead of shutting off. I don't remember how I found this solution though. I think I realized that my computer kept restarting when I didn't go online (thus establishing a dial-up connection). Here's a screen shot of all devices on my computer.

Hi there, I'm using Windows XP SP2. I have a strange problem which began to occur about 6 months ago. My computer doesn't shut off unless I click on a dial-up connection. If I dont't do that, it restarts. I think it's something about my modem. It's an interesting one. What could you recommend me to solve this?