Am I Crazy? Dual Boot 7 Pro & 8.1 or 10?

Hi Folks,
I already know I'm crazy but..... I have my first Windows machine, DELL 5558 laptop with a Core I7-5500UCPU @ 2.40GHz, 1-TB HD, and currently 6-GB ram which I will max out to 16-GB when I get the chance. No touch screen! It came with 8.1 installed, I upgraded to 10 and all was pretty OK until I broke it with a stupid move in "Command Prompt" and then reset it back to factory settings! What I would like to do will void any software warranty and support from DELL, but they say they will still support the hardware.

In a nutshell, I want to eventually end up with a dual boot machine supporting 7 Pro and hopefully 10 Pro. I am at least aware enough to realize that I'll need to re-partition and undo much of the DELL "proprietary" backup and recovery configurations.

I'm not a gamer and simply want to learn how to keep these machines working well in a productive business environment! I will not likely use many applications, other than a few electronic schematic/layout drawing programs and the full suite of Office. My spare time (what little I get) is spent playing guitar and singing in a Blues/Rock band and custom building vacuum tube guitar amplifiers. All recording and other music related tasks are already easily handled by my MAC's!

You see, I've just started school for A+, Network+, Security+ and probably on to Cisco training and certifications. The school I'm attending has all 7 Pro machines and won't likely upgrade soon, especially given that the CompTIA textbooks and exams barely even acknowledge the existence of Windows 8 yet. They will likely upgrade within the next year or so. I've been a MAC guy since my first confuser in '98 and figured that I should get a Windows based unit for my training, but 8.1 and 10 are just so vastly different than 7, that just getting through the differences in the changes while familiarizing myself with the whole Windows experience, along with trying to learn how to be a tech for them, is pretty daunting, at best!

I have purchased Windows 7 Professional on a disk with key and DELL has sent me a recovery disk with 8.1 Home, with a product key (just in case I really fork things up!) and as soon as they are in hand, I will begin the process.

Where do I start? What do I do?
Thanks In Advance,
Gene

The best reason for him requiring a dual-boot configuration is that he aspires to be a computer technician. Computer technicians should know how to do something as simple as setting up a dual-boot system. (simple from perspective of a professional computer technician)

To the OP, make sure you install your operating systems in "UEFI mode" and NOT "Legacy/BIOS mode".
To do this, you must boot the installation CD in UEFI mode. Read your laptop's manual (pdf at dell.com support available) to determine how to do so.

(Only relevant to HDDs, ignore for SSDs)
When partitioning the hard drive, ensure that the OS you intend to spend the most time in, is as close to the outter edge of the disk platter as possible but still behind the boot partition. This maximizes performance.
When using a visual partition editor, the partitions furthest to the left are closer to the outter edge of the platter.
When using a commandline or non-visual partition editor, usually the lowest numbered partition is closest to the outter edge.

Finally, create a large partition for the data you'll want to use from either of your operating systems. Data like pictures, archives & backups, a game or two, portable applications, anything work related, etc. This is to avoid a problem I've had people bring their computers in for. When dual-booting, unless you have somewhat indepth knowledge of windows and NTFS permissions and know how to clone your user SID from one OS to the other, you'll want to avoid ever accessing (especially the Users directory) the other partition from the one you are booted to currently. Windows will clobber permissions which can be hard to figure out when you cannot log in to one OS, or your explorer.exe process keeps crashing. (due to NTUSER reg hive being inaccessible)

Oh and before you install windows 7, make sure you download your wireless/lan drivers from dell.com first. Sometimes Windows 7 lacks network drivers, which sucks big time when you have to reboot 3 times just to realize its time to start the loooong windows 7 update process.

Hydranix said:

The best reason for him requiring a dual-boot configuration is that he aspires to be a computer technician. Computer technicians should know how to do something as simple as setting up a dual-boot system. (simple from perspective of a professional computer technician)

Even more reason to virtualize. Very little, if no reason to install multiple operating systems natively anymore. If a person is using this computer to learn and gain experience, why would you want them to close out and restart every time they wanted to do something with another OS? One system issue and you could render the entire computer unbootable. Keep it simple and keep it clean. Virtualize!

CountMike said:

In a nutshell, you'll need to make a new partition on your disk or even better, to ad another disk to install W10 on it.
Now for W10 itself, you can't use that windows 7 to get W10 for free by upgrading and install W10 as another system. You need either full retail version of W10 or new W7 or 8.1 that wasn't already registered with MS.

Not the case with the OP. He has already upgraded the Windows 8.1 on this computer once to Windows 10 - so a Windows 10 clean install will activate itself by skipping the product key. Then the OP purchased the Windows 7 to install.

windoz said:

Hi Folks,
I already know I'm crazy but..... I have my first Windows machine, DELL 5558 laptop with a Core I7-5500UCPU @ 2.40GHz, 1-TB HD, and currently 6-GB ram which I will max out to 16-GB when I get the chance. No touch screen! It came with 8.1 installed, I upgraded to 10 and all was pretty OK

If I were the OP, this is what I would do - everything on the computer will be erased on the first step:

Boot from the purchased Windows 7 install disc. Do a clean, custom install, deleting all the partitions on the hard drive and pointing the install to the unallocated space. Install the drivers for the laptop, get Windows 7 running good and solid. Install MiniTool Partition Wizard Free to increase the 150mb system reserved partition that Windows 7 will make to 350mb, shrink the Windows 7 partition, make a Windows 10 partition and format it to NTFS.

(see my last sentence in this post - might want to put Windows 8.1 here instead) - Boot from the Windows 10 install disk/USB - using the same Windows 10 version that you got when you upgraded from Windows 8.1. That is important because your Windows 10 won't activate if you try to install a different version. Do a custom clean install, this time point it to the already formatted partition that you created for it earlier. Skip or "Do this later" when it asks for a product key. Windows 10 will install to that partition, set up dual booting automatically, and should activate itself if it is the same version that was on the computer before.

You can't dual boot your Windows 7 Pro AND use that to upgrade to Windows 10 Pro without violating the EULA.

Now - if you install Windows 8.1 Home as the second OS instead of Windows 10. Then you can upgrade the Windows 7 installed in the first step to Windows 10 Pro and not violate the EULA.