car still not running beleive it a fuse but can't find the right one

It's the fusible link...this should help. http://www.clublexus.com/forums/is-2nd-gen-2006-2013/692433-dyi-fusible-link-removal.html

Unless you are a very lucky person .. the odds of putting your finger on the problem by "peck and hunt" are remote,,, and chances of finding the problem become even more difficult if your knowledge of cars is not that good, Mechanics use a method of isolating if the range of possible causes is very large .. by first generalizing the area into 2 regions ... then they eliminate one region and put the next area into 2 regions ... they keep doing that until the problem is found. You failed to say if anything works. We can narrow down where the problem is if we know what was not effected ,,, but to simply say "It won't start" is an almost impossible way to fix your problem

radio heater windows air anything that is electric wont work replaced new battery and alternator and fuses but still not everything on car is working

Probably what joemom said ... and NO ,, there is no "BATTERY BACKWARDS" fuse ...Probably due to no-one ever puts a battery in backwards