Can I run Windows 7 32 (bit) on pentium 4?

I have 1 GB RAM, 2.4 processor, 40 GB Hard Disk. I run windows xp but now I want to run Windows 7 32 bit on my computer. Is it possible ? What will the speed of the computer after installing win 7. I have HP desktop. How can I know that how much RAM I can use ? Could I still extend memory ?