Windows 7 on a Pentium 4?

It can be done, but a "custom install" according to Microsoft. I do have a 32 bit system. They have a gadget to check your computer and give you a report. I did this with one of mine -similar to yours. You will have to step forward in RAM though. 3GB would be wise. With that CPU and the 800 MHz FSB, you should be equipped with hyper threading. This helps too. Give these people a try and see what is said. Hope it helps.