Hello thanks for your reply.
Unfortunately in the meantime the situation has taken a turn for the worse. Being impatient, I located some instructions on this thread http://www.daniweb.com/forums/thread55438.html
which for some reason I took to apply to my problem.
So, after following user Stein's instructions, I restarted my computer and was then met with a 'Driver_IRQL_NOT_LESS_OR EQUAL' BSOD, accompanied by some pretty colours flashing along the bottom of the screen and some horizontal stripes along the top, both of which I imagine shouldn't have really been there. This was as much as the computer could do, since it still doesn't want to start in safe mode.
After repeated turnings on and off it has now revived. There is I suspect quite a serious problem - the error report that got sent to the nice folks at Windows was corrupted. In your opinion it worth my while to try to fix this or am I better off wiping the drive and reinstalling the OS (don't have many programmes to lose)?