Move Your PC Components From the Old Case to the New One
The process of transferring components from one case to another is in some ways simpler than the process of selecting the new case. Start with the components that you can easily uninstall, move, and install without affecting any others.
In a typical system build, I like to start by disconnecting all of the wires and power cables in my existing chassis so that I can get the rat's nest out of the case before I try to remove individual components. Pull out the SATA cables and the power supply, and disconnect other wires inside the system. Then pop off your system's side panels, remove your case's front panel (if applicable), and remove your 5.25-inch optical drives. Depending on the design of your new case, you might be able to load these components into the new shell immediately--one reason I love tool-free case designs. Hard drives come next, and they merit the same treatment.
Next, remove your PCI devices, which might consist of a single discrete video card in some instances. Assuming that you aren't running some fancy water-cooling setup, your old case should be empty of practically everything but the motherboard by now. Unscrew it and gently remove it from the case, gripping it by the edges.
If your new case doesn't come with motherboard standoffs, screw them in--and install your motherboard's I/O shield--before attempting to install the motherboard itself.
Once the motherboard is in place, I usually attach the system's PCI devices, especially the video card; however, this approach may make for trickier access to SATA ports or other connectors, depending on the motherboard's layout. On the other hand, waiting to install the video card can pose a bit of a challenge if the power cables on the power supply barely reach the top connectors on the motherboard.
Once all of your components are in place and you're ready to start connecting cables, try to use your case's built-in cable management options to maximum advantage. In most systems, the goal is to route as many cables as possible behind the motherboard (mashed up against the right side panel). For this purpose, cases that provide multiple routing holes around the motherboard tray or fasteners (for twist ties/Velcro strips/twine or the like) behind it can be immensely helpful. Minimizing clumps of cables in the middle of your PC will give the system better airflow.
Next, examine your case layout and verify whether you need to install the power supply at this stage. I recommend waiting until the last possible moment to install your power supply, to avoid having to deal with a bunch of loose power cables. Unfortunately, some cases make it hard to install your power supply after the motherboard is in place, so plan accordingly. Once you've installed the power supply and finished connecting all of the system's cables, you should be finished.
Transferring components from one case to another isn't especially difficult, even for computer newbies. For most people, the most time-consuming part of the operation involves cable management--unless you're migrating a relatively tricky system build (such as one featuring a liquid cooling loop) to a case that may require some creative thinking to achieve the desired results.
Don't be afraid of cases. Buy one. Build a system in one. You'll be amazed at the options that await your consideration--including plenty of builder-friendly features--on today's market of well-priced, well-designed chassis.