Ya i really wish you would of typed your problem a little better your text is a little confusing. but im gonna try to help. first of all i would not of set this up the way you have it set up.
you can use get and post you need to pick one of the other when gathering the information. so if someone is trying to log in with a for and the action is post but then in your authentication process you are using GET its not gonna work right.
the reason you see OP=login in the URL is because when you use the GET method it post the information to the URL.
So to start with... cause I am not to clear on where the page is directing you when you login. you did not specify that to clearly. it sounds like it is just posing the GET value to the URL. Change the GET to POST and see if that fixes your problem. If not I think we might have to rewrite your script. Ill post one to give you an example.
I really advise against having forms in pages posting to them selves. for some reason I have noticed a lot of people posting questions where their forms dont show up or behave correctly and when you make the action method in the form point to another page and put the php in that page everything seems to work fine. I am not sure why that is maybe someone with more experience then me would not mind explaining it.
Please retype your question and be more clear about what your seeing before you execute anything. and then what your seeing after. such as if the page redirects what does the URL say?
