"A factory restore will mean I lose everything won't it - photos etc."
the only way round that would be to take it to a lap top "specialist" who will take the HDD out and should be able to grab your files and put them on DVD or flashfdrive or whatever you want.
Depends how valuable the files you want are.
Or If you can get hold of an original Windows disk do a re-install, you may get out of trouble, when it installs it will ask you if want to make a new partition to install to, which will leave the current installation intact so thats one option, it also if you re-install on the current partition will make a folder called Windows old, which will have your files if they were saved to the Windows default locations in My documents.