1990 gsx cannot get into 1st or 2nd gear

[CarPsyco84]

First thing to check is that your clutch is releasing all the way... If your stopped, find a gear it will go in, push the clutch in, go to put it in gear, if you go back to neutral and then put it back in that gear, it should be right there, shouldn't feel the syncro's have to work to stop the tranny shafts again. If thats ok, you might have moved the shift cable bracket that holds the cables mounted on the tranny, also the shift linkage is adjustable inside the car also, which can help.