This has happened when I had my desktop computer but then I would get a lot of blue screen errors. Now, it’s like if I try to leave my laptop on, eventually it shuts down and I have to restart. The reason why I leave it on is because often when I’m trying to download something, I’m way back in the queue and not wanting to sit here for hours waiting for my downloads to start, I just leave it on. Does this happen because WinMX isn’t that stable or what? 
I don’t know about your laptop, but I know why this thread is going to shut down.
Windows 2000 and XP can be set to reboot automatically in the case of a bluescreen, and this may be what’s happening. You can change the default behavior in the System applet in Control Panel. Click the button on the Advanced tab under Startup and Recovery and uncheck Automatically reboot. This will at least let you see any error messages that come up when the system crashes.
Twit, I would email a mod, and ask them to shut this thread down. Due to the illegality of certain types of filesharing, it’s considered a no no to talk about it here.
[non-pit rant]
Jeez, this kind of thing really pisses me off. NO ONE’S TALKING ABOUT FILE SHARING HERE!!! This is a computer/OS problem which has likely been solved by Number. Twit is just asking for some tech support here. What is the f*ing difference if the op had been: “Photoshop causes my computer to restart”.
I understand the regs about file sharing threads, but come on. Mods, please be reasonable and don’t make it like PeeWee’s Playhouse where when one secret word is uttered, everyone starts yelling and screaming. Everyone else, stop trying to be a Junior Mod and stick to fighting ignorance.
[/non-pit rant]
Although I think **Number **has got it, I had a problem with sporatic rebooting which ended up being a result of my box overheating. You might want to check your fans/temp.