Ubuntu mounted the drive itself, otherwise you could not see the data. At this point, I would do a backup of the important files on another drive, if you have one.
I suspect the filesystem got corrupted because the HDD was accessed during the outage (not your fault). See here:http://www.ntfs.com/partition-recovery-concepts.htm
for some explanations.
To get it to boot properly, You will need to boot from Vista CD/DVD and start the installation; when it asks you whether to perform a clean install or to repair an existing installation, choose the later. Then, point it to the existing installation that needs repairing and follow the repair wizard:http://www.bleepingcomputer.com/tutorials/tutorial148.html
Remember, always backup your data first, in case the unexpected happens.