optifine= gray screen :(

[BigDigLover]

Ok so I have already heard some people say it's not worth it or it causes more problems than it fixes but I wish to be the judge of that myself. That being said let's move on to my issue.

I have already tried\

optifine 1.5.2 U

optifine 1.4.6 hd and U

No I did not put more than one in at the same time

These are the ones I was told I would need but regardless they all caused my mojang screen to be replaced with a gray screen and my game would not load leading to me having to delete the mod and mc jars. Yes I placed the files from the optifine downloads into the modpack.jar not the minecraft.jar

So that being said am I putting the wrong ones\

Am I doing something wrong\

Assistance would be greatly appreciated. Thank you