I'm at a loss for ideas honestly. The laptop will just randomly shut off. It's happened both plugged in and on the battery. It averages probably 1 time a day or less. Otherwise it works terrific. I get no errors from Windows XP. It just shuts off completely with no warning. Screen black, no power, and hard drive off. I've worked with it for a while and haven't seen this before. Started randomly. The only part that isn't Lenovo on it is the battery, which might be causing the issue. Got an el-cheapo replacement which works great and holds a good charge. My only guess would be that something is short circuiting somewhere once in a while. But as to why...I have no idea.