Take these steps now
Most likely file corruption has taken place due to the abrupt power loss. I would suggest taking the following steps. Begin to immediately BACK UP any essential documents and files. Begin the process of trying to repair any corrupt operating system files:
Go to the Start Menu
In Search type: cmd
Before running cmd.exe, right click and "Run as Administrator"
You will see a black console
Run the command
sfc /scannow
This will verify that the Windows operating system files are not corrupted or altered. If you continue to experience the issue, or not, you need to completely scan your hard drive for corruption. Do this after you try to repair the OS files.
Using the same method above run
chkdsk /r /f
From the command-line.
Respond with "y" to all the questions and restart the computer.
The next step, if none of this works, is to initiate a System Restore. To initiate a System Restore, go to Start - > Search and type "System Restore"
Restore back to a time
before the computer lost power. Using these three steps:
sfc /scannow
chkdsk /r /f
System Restore
You have a good chance of repairing the system. However, if these methods fail, you may want to get the Windows 7 DVD media out and run an Upgrade install from inside Windows or completely re-install the operating system.
If you do have some success fixing the problem, I recommend you start performing, at the very least, monthly backups. To see how this can be accomplished rather successfully and without any doubt, you may want to try acquiring some 3rd party software rather than rely on Windows Backup, which has often times been a big headache for everyone.
See this blog and video:
http://windows7forums.com/blogs/mike/247-how-perform-bare-metal-backup-recovery-video.html
Good luck, and please tell us your result!