C drive

There are serveral possibilities:
First, your window system was corrupted.
It may be caused by some virus that delete or modify some important window system file, so when your PC try to boot into the window, it becomes very unstable.
Secondly, your harddisk is damaged (some partition of harddisk), so you found something in the C drive and the file type is "$$$".
Thirdly, your motherboard or Power was not function correctly, that make your computer on and off on and off automaticly.
You should troubleshooting the above point one by one and find out the reasons of the cause.

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