If you manage to get your old Pentium 4 to run with Windows Vista, do you think it would be ready for Windows 7? I personally think that the time for single core processor is over.

Even with dual core processor and running on Windows Vista is pretty slow. Of course this is after comparing to Windows XP or Windows 2000.

In the old days, 1GB is recommended RAM to run Windows XP. Today, 2GB is the bare minimum for reasonable Windows Vista performance. And I expected that 4GB to be the minimum by the time Windows 7 ships.

If you like to still using Windows XP, I recommend that you get a system which is ready for quad core processor. If you buying a new computer which the motherboard only supported for dual core, then by time Windows 7 ships, you might need to get a new motherboard that can support quad core processor.