Black screen
Verify the ISO or disc image; try software vs hardware rendering; switch Vulkan/OpenGL; disable widescreen hacks for a baseline boot.
Fixes
Troubleshooting
Start here: most PCSX2 issues come from bad dumps, wrong BIOS region, or changing too many graphics settings at once. Confirm your game image and BIOS first, then try switching renderer (Vulkan/OpenGL) before raising resolution. Change one variable at a time and note what you changed so you can undo it.
Low FPS
Lower internal resolution first; watch OSD for EE/GS limits; close background apps; match sync and frame limiter to your display.
Controller issues
Remap in PCSX2; try XInput vs DInput; reconnect after sleep; duplicate profiles per game if mappings differ.
Audio stutter
Stabilize frame pacing; adjust audio stretch/sync modules; reduce load so the CPU is not starved.
Still stuck?
Collect PCSX2 version, OS, GPU model and driver, renderer, and the last few log lines. Compare with compatibility notes for that game before opening a thread.