Windows 7: Strange crash lately

I haven't add or remove a thing from the pc .. no problems when doing a restart but if I shutdown and later start I get The error NO OS twice and then it start normal.. mind you I hear a noise from the box like a little nudge before it crash.. tried to get mini dump file but none there I have disabled the auto start after failiur so I can get a dmp file but none created , done the sys. restore , scanned for
viruses and spyware,chkdsk and sfc /.. and start up repair and mem check and all clear .....and bios is set to start from HD I looked in Event viewer and attached a file .
Grateful for any help..Thanks

It must be a good one... any Idea..thanks