Symptoms are not catastrophic or even very helpful to isolating "issue."
The next to the last install starts, e.g., Platinum logo comes up, then just simply quits.
No errors, no lingering half loaded drivers, nothing left in RAM, it just stops. and I can run the LAST installed version (32 or 64) right behind this "crash" with no ill effects.
I just went back and tried this with X3 - identical behavior (installed 64 first, then 32 second: 64 bit won't start but 32 will start: then reversed install order of X3 (32 then 64) and which version that runs is reversed.)
OH well (BTW this is WIN 7 64 but it should make no difference)
edit:
This has nothing to do with opening songs saved in "other" version - just opening program has issues
thanks for helping