Hi there I own a Compaq Deskpro EN minitower computer and I am having serious problems in installing new hardware due to hectic case design. I would like to install all the hardware of this computer in a new case (e.g. ones from Asus or AOpen). Is it possible? Thanks.
I really don't see why not. If anything, you should be able to snag a mid-tower case from AOpen for around $40-50 USD, including a power supply. Should give you a bit more room. If you really need to have access to any front mounted ports, you'll need to look a little harder for a case. Barring that, everything else should work.
Your should be able to move the hardware to a new case, although adding new hardware I'm not sure if you'll be able to do. In the past Compaq has been notorious for only being able to be upgraded with their own parts. I'm not sure if they've changed or not so you might run into problems trying to add the new hardware.
