What an ordeal!!
I started reinstalling Windows on Friday night (about 9pm) after I'd made sure I'd backed up everything I could possibly think of!
I was probably about 2/3 of the way through installing & reloading everything by 3pm Saturday when I realised that I couldn't run any of the websites that I develop on my local machine. A huge issue! 2 hours, much Googling and many attempts to fix it later, I gave up and started installing Windows - again!!!!
Its now about 11am on Sunday and fingers crossed that I am all back.. Everything seems to be installed and working ok. I'm sure I'll find stuff that I've forgotten to install - probably just as I go to use it - but I should be able to get back into my work and online world now :)