Yeh I have AMD Mobile Sempron Processor. Extract from Wikipedia regarding Sempron 3500+ model CPU's:
"Keene" (Socket S1, F2, 90 nm, Low power)
All models support: MMX, SSE, SSE2, SSE3, Enhanced 3DNow!, NX bit, AMD64, PowerNow!
After so more research found out my CPU supports 64bit -only...