Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).

• Don't make any changes on the Safe mode start window.

See:

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

Still no luck, if i minimize a window a firefox icon appears at the bottom of my page but if i open another window and minimize that window it overrides the first.

My old Laptop was fine i could minimize as many windows as i wanted but not with my new Laptop, the only difference between the 2 is on my new one i have windows 7 my old one just had Vista. If i change to Internet Explorer i can minimize ok but lose my spell check facility.