Hi Narimato.
This question should be asked in the
Microsoft Community for Windows, which is more appropriate for this kind of topics.
The first action to take is checking the "System" log in the Windows Event Viewer to see if there are records that can provide you with more detailed information about any system event that could be related to this problem; also contact Lenovo Support
and ask for assistance, since the problem could be hardware related.
Bye.
Luigi Bruno
MCP, MCTS, MOS, MTA