Razzle, what brand computer do you have. Sometimes its best to use the hidden partition that most major companies install and put your computer back to the way it was when you bought it. Is your computer a Dell, HP ?
There are many tools available out on the internet to help get your computer back running great again if you do not want to reformat. I have been repairing computers for over 15 years now and if you give me a little more info maybe I can help. Tom