If you're running Windows Vista, just go into the Control Panel, System, and check the ranking. Otherwize, yes, it is a fast system.
Yes. You can upgrade your Dell XPS 400 Intel Pentium D to Intel core i7.
Laptop graphics cards are generally considered to be impossible to upgrade.
By upgrading the graphics card.
upgrade for hardware required ......
That would require purchasing a new motherboard, processor, and power supply.
You can upgrade your laptops graphics. You will need to see what type of graphics cards your computer is compatible with a choose one to your liking.
No you can't.
No, the graphics chip is embeded.
The Intel Pentium 4 3.0 GHz processor is a single core processor, but if you'd like to upgrade to dual core, have a look at the Intel Pentium 4 531 3.0GHz Processor Upgrade RH008AV.
Yes, you can. The motherboard is equipped with a PCI-e port so you can plug in a graphics card.
No both graphics card must be the same.
You will at least need a new motherboard. The rest of the hardware in the Pentium II is probably so old that I would buy a new computer instead which has all new hardware.