1. Is there a way to convert .76 roms to .36 roms?
2. I have bought the official Metal Slug collection for my PC. It contains original roms of Metal Slug 1,2,3 & X. How can I get them running on my PPC?
Sadly i havent a clue how to convert .76 roms to .36 roms. Even then it probably wont work. You can display a list of roms which can work on MegamameCE but if Metalslug doesnt appear on the list it wont work whatever
You cant easily get any PC games running on the PPC.
However i did see that there is a Metal Slug game for the Gameboy Advance, you could download that game and then use it with an emulator (If your PPC is fast enough)