The Sims 2 is a 2004 game that needs help running on modern Windows. Provide your OS, exact error, installed expansions, and tried fixes for precise help. Meanwhile, start here:
TS2EP9.exe (or base Sims2.exe) to allow >2GB RAM usage.GraphicsRules.sgr / VideoCards.sgr files.Install in release order: Base → University → Nightlife → Open for Business → Pets → Seasons → Bon Voyage → FreeTime → Apartment Life → Mansion & Garden / Katy Perry / H&M / Teen Style (stuff packs).
Reply with your specs and error details for targeted help.