no it is not possible. only the new generation of dell's may support ddr2.
your system is quite a few years old. it may only support ddr ram
Nope. My Dimension 8400 from 2 years ago has DDR2 memory. If it's older than that you may be right, but if it's newer or same age it should have DDR2. Just download CPUZ from www.cpuid.com. It will tell you about your motherboard and ram.