galaxy s4 gt-i9505 firmware upgrade encountered a..

Being a Root virgin,i had a play with my Samsung Galaxy s4 gt-i9505,i managed the first part ok but then i went a bit crazy and tryed installing the first rom i seen,which now i can't remember what it was.....ended up getting "firmware upgrade encountered an issue........" have trawled the net caught virus after virus trying to get something to work,kies or kies 3 dosen't seem to pick up my fone tryed installing reinstalling but nothing entered model and it told me wasn't supported,have tried odin,several different usb cables,seemed to pass first i managed to root but now its fail after fail,only computers i have both run 10....completely lost
thanks in advance :crying: