All I can think of is the Malware you ran into corrupted the registry, the problem I have is why only Firefox. I guess it was the browser being used at the time.

 I wonder if you go to system restore and restore to a point before Firefox wouldn't open. I know this sound drastic but i am running out of options for you.

  http://windows.microsoft.com/en-US/windows-vista/System-Restore-frequently-asked-questions

I'll try I got nothing to lose

Well it didn't work but I seem to be able to use firefox if I run as an administrator I don't get it

Maybe something corrupted the Windows User profile. Make a new one and see if Firefox will start. If it won't then we have to assume that Firefox was installed under Administrator only.

 When installing as Administrator you are asked if program is to used by everyone or just Administrator.

I think you can change an Administrator only to permission for Users. There is a setting in the file properties of an exe file that says run as Administrator, if you unchecked this box you should give permission to users.

 Right click Firefox icon and open properties and look at the Compatibility tab, at the bottom of page.

I have done all these steps and it's still the same

Well I guess you could remove the two folders and reinstall as a limited User.

 But of course the question of why could you not even open Firefox until you restored to a previous time lingers, and now only as Administrator.
 I think you should bite the bullet and reinstall Firefox. I would just rename the two folders by adding old to the front of the names, then if you wanted old bookmarks or something you could go back and get them.
 But with that said it is possible you could install Firefox from the limited User profile and leave the Administrator copy there, I am guessing that a new Profile folder would be created for the limited user profile.
 I don't really know much about limited User, I always run as Administrator. Of course this is said to be risky, but what is life without a few.

I never ended up doing a system restore it wouldnt work I'm eventually gonna back up my laptop and just reformat it's been years. I will uninstall firefox again and try what you said.

I saves my bookmarks the first time I reinstalled so I will just import them after the new install. I am the administrator so I don't know how it would install any other way but I'll try creating another windows profile and seeing what happens

Well it works perfect under my husbands account but not mine thats the weirdest thing ever i can still only open it by right clicking and choosing admin option