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Firefox Does Not Start After New Install

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Firefox will not start after new installation on Vista platform.

After I installed Firefox on my PC

User Agent

Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; GTB6; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C)

Firefox will not start after new installation on Vista platform. == After I installed Firefox on my PC == == User Agent == Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; GTB6; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C)

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Try these three possible solutions

If you close Firefox, then start Firefox in Safe Mode, does the problem still occur? For instructions on starting in Safe Mode, see Diagnose Firefox issues using Troubleshoot Mode.

Extensions can sometimes be the cause of problems. If the problem does not occur in Safe Mode, then you can disable your extensions one-by-one until you find out which one is causing the problem. See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

Your Firefox settings and info are kept in a folder separate from the Firefox program, called your profile folder. Try creating a test profile, to see if the problem still occurs. See Profile Manager - Create, remove or switch Firefox profiles