You still have P, Q and O in your new system but in other equations you have PP, QQ, and OO...
It should be one or the other right?
I edited the system and run solve with the parametric and real options, solve(sys,vars,'parametric','real');
See solve/parametric in the help section. But even using 4 processors and 3G of memory I get an error:
GC Thread signalAbort 0x2aaad5341940 Execution stopped: Stack limit reached.
maple: fatal error, lost connection to kernel
My guess is the system is too big for Maple to handle. I suggest selecting some numerical values for some parameters and trying it with a smaller system.