Clutch does not engage when I need it to go into first or reverse

My clutch refuses to engage when I need it to go into first or reverse. But while I'm on the road it engages smoothly. As soon as I come to a stop and need it to go to first gear it will refuse to do so! I have to turn of the ignition put it in first in able for me to drive. Inspected in and around the car for any leaks and found none, I bled the clutch line, even replaced the slave cylinder do to its location and of ease to get to (hoping it was just a bad slave) and followed the appropriate protocol that is done (but not the master quite yet) -but saw no hopes in fixing the matter. Any suggestions would greatly be appreciated. I'm really hoping it's not the transmission. Oh, I also replaced the whole clutch system a few years back with a ACT clutch kit (A shiny penny it cost me). Would I need to replace it again I wonder?