You say you have no windows 7 disks, usually pc world and a lot of other manufacturers give you a support disk that should put your system back to the default setup, like when you bought it. The files needed are usually on a hidden partition. Do you have this disk ? , or ask pcworld if the partition exists and how can you access it.
Other thing to try since you say you may have interrupted the power supply is a full sector scan. Also start up in safe mode and disable your disk cache, then delete the pagefile.sys file reboot then re- enable it. Just a few idea, hope they are of help.