Now when I reinstall it again it says "user not found". I again uninstalled and deleted the mozilla folder in appdata and everywhere I could find firefox or Mozilla folder. When I reinstall its all successful but says User not found. Even if I hold Shift and try to start it in safe mode. How do I install firefox again? I would be happy to just install Chrome but its a friends laptop and if they try to install FF then they will face the same problem. So I need to clean out FF. Why I did this? I had FF installed on my friend Laptop as I had borrowed. I had imported all my username passwords etc. So when returning it i wanted to deleted. For some reason I could not find the reset option. Or I used safe mode but it did nothing. So i just went and deleted my profile folder. I thought if i did that then when I start firefox it would automatically build a new user. But I was wrong( FOR CRYING OUT LOUD WHY IT DID NOT HAPPEN?) So I uninstalled it and reinstalled(I selected not to keep my settings ) even then it did not work. Kept giving me a alert saying user not found or something like that. Then it would not start. So I whent and deleted all mozilla and firefox folder in my C drive(after uninstalled FF again) still the same. Now I am just flumoxed!! I can't believe that such thing could happen like after uninstalling it. It is so frustrating I just am fed up. I tried googling but could not find anything to help me. Using Win7 fully updated and I tried installed the latest version of FF