I think you'd be better off cutting your loses and reinstalling windows, just save all your important documents onto a usb flash drive or something(can get them for £5-10 on amazon) then stick the windows disc in and away you go

You could do it your self probably, just follow the on screen instructions, click a few buttons, and its done, then just let windows update on its own(again clicking a few buttons) and then stick your personal stuff back on, thats all there is to it.

The whole process should take about 1 hour/1 hour 30mins