What might have happened?

Howdy,
Last night, everything seemed fine. Did a Macrium BU, ran McAfee security scan deep, ran MalwareBytes Scan, surfed the net. No warnings or cautions. Checked email.
Answered email. Downloaded newest Zonealarm Free Firewall, didn't install it. Programs that can updated their defintions. I believe that is about it. System is homebuilt and new and running good (?). Did have a power outage earlier in the day. Booted to normal windows (Windows 7 Ultimate 64-bit).
Turned on this morning and left room. Came back with Message to do System Restore or Fix startup. Without caffeine or thinking hit Fix Startup. Ran a while and started, not enough caffeine or sense to write down any codes or anything, IIRC it said 1 error. Rebooted and checked my BIOS, seemed OK. Booted, ran sfc /scannow with no problems.
My question is: What happened, what is the most likely cause with the current info, Is it safe?(Marathon Man)? If not, how messed up am I. Is there anything I should check? Everything appears to be working appropriately, 1/2 necessary caffeine.
Thanks for any input. New to W7, skipped Vista, anxious!!!!!
glennc

Morning richc46,
Brilliant idea. Got to event viewer, never saw one before now. I went to Event Viewer, and then lost the ability to follow your directions.

Look for the problems that occured at the time of the shutdown. There will be codes and explanations. Look for errors.

I see no obvious way to find anything by time. I see codes like I went to Event Viewer/Local and found errors in Summary of Administrative Events, opened errors, in the last 24 Hours I have 21. Am I anywhere close to where I should be??
glennc

richc46,
In the Middle column at the top it currently indicates a bar in dark gray Event Viewer (local), under that is a lighter gray bar which indicates Overview and Summary and Last refreshed 7/20/2010 7:51:09 AM. I have a feeling this is not what you meant!
glennc

Back again richc46,
Under Custom Views, I found Administrative Events with a list of dated errors and warnings. At around the time I shutdown I see a SideBySide Error, a within 32 seconds another SideBySide Error. At approx 17 minutes before that is a User Profile Service Warning something about 1 memory item leaked From Registry something Superantispyware\SABUpdate.
Mean anything to you?
Thanks dude!
glennc

Here you are, the ones around midnight



Hope it helps
glennc