What to do? Help me plz!

Dear all,

I have two questions and I look anxiously for answers.
The first one: Yesterday, while I was playing a game, the electricity fell to 200 Watts just for a second or maybe less and then again at 220 Watts. The result was that the PC restarted and after the “Welcome” screen a message appeared that said “Your System has recovered from a serious error. Click below to view the log files.” I checked the files that were xml and data in a category of the windows folder. I kept them in a folder to prevent losing them by mistake. I did a check volume for errors (no problems at all) and cleaned the junk registry files with the System Mechanic Program (no problems also). When the system rebooted, the same message appeared. I don’t know what to do. Do you know another way to fix it except from formatting the disc? Please help.
And the second one: When I defragment the System Volume, the log box that shows the non-defragmented files is empty. Has anyone got an idea why this happens? Is it because that maybe the files are hidden?
Thank you in advance.