how to "unpatch" cod5

ok, well, i want to go back to the 1.4 patch, how do i do that. i have 1.5 installed, like i basically want to uninstall 1.5

why do you want to return to a lower version no one is playing online on that anymore :S i have no cracked version and online playing goes quite well you just need the seem patch thing as you need to use in 1.4

kus, me and my friend have this hack thats only for the 1.4 patch, and theres still servers on 1.4 so i wanted to lvl up some on 1.4 then go back to 1.5