1) save your current E-machine's HD
2) on the E-machine go into device-manager and uninstall all your hardware.
If you have PC-specific drivers like VIA unsinstall there as well.
3) ghost this HD for transplant to new PC
4) copy the original save from step 1 back onto E-machine, so it keeps its functionality
5) copy ghosted file from step 3 onto new HD in Compaq. When you startup this PC, all hardware of the new PC will be re-installed.
However, it is not a good solution. Better to make a clean install, setting the Computer to be a Standard PC (NOT the ACPI type).
Search the other forums to show you how this is done (it is all out there)