Please be more specific, I have no idea whats the problem

Probably your security software blocking Firefox, see : [https://support.mozilla.org/en-US/kb/Firefox%20cannot%20load%20websites%20but%20other%20programs%20can Firefox cannot load websites but other programs can] see also: [https://support.mozilla.org/en-US/kb/Firewalls Firewalls] thank you Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.

try ctrl + r then type firefox.exe all lower case this will run firefox