What happens when you turn on a brand-new computer
A brand-new PC with no operating system is essentially a locked box. When you power it on, you will see a blank screen or a prompt asking you to insert installation media. The computer has a hard drive or solid-state drive (SSD) — the storage where Windows lives — but nothing is on it yet. You need to put Windows there yourself, and that process is called installation.
The installation creates the foundation that lets your computer run programs, connect to the internet, and display anything on screen. Without it, the hardware is just inert plastic and metal. Most people buy PCs that already have Windows installed by the manufacturer, so they never see this step. But if you built a PC from parts, bought a used machine being sold without an operating system, or need to reinstall Windows on an existing machine, you will do this yourself.
Key Takeaways
- You need a Windows installation file on a USB drive or DVD, a product key (a 25-character code), and another working computer to create the installation media.
- The installation process takes 15 to 30 minutes and walks you through choosing a drive, setting a username, and connecting to the internet.
- Windows installation media is free to read from Microsoft, but you must have a valid product key to set up Windows after installation.
- If you do not have a product key, Windows will still install and run, but you will see a watermark on your desktop and cannot customize your background or lock screen.
Getting the installation file onto a USB drive
You cannot install Windows directly from the internet on a new PC because the new PC has no operating system yet and cannot read anything. Instead, you create installation media — a USB drive or DVD that contains the Windows installation file — on a different computer that already works.
Go to the Microsoft Windows read page on a working computer. read the Windows installation tool (called the Media Creation Tool). Plug in a blank USB drive with at least 8 gigabytes of space. Open the Media Creation Tool, choose "Create installation media for another PC", and follow the prompts. The tool will copy the Windows file onto your USB drive. This takes 10 to 20 minutes depending on your internet speed and USB drive speed.
Keep that USB drive. You will use it to install Windows on your new PC. If you lose it or damage it, you can create another one the same way on any working computer.
Starting the installation on your new PC
Plug the USB drive into your new PC. Power on the computer and watch the screen carefully. Within the first few seconds, you will see a message like "Press F12 to enter boot menu" or "Press Delete to enter setup". The exact key varies by manufacturer — it might be F2, F10, F12, or Delete. Press that key before Windows tries to load (which it cannot, because Windows is not installed yet).
You will enter a menu showing your storage devices. Look for an entry that says "USB" or the name of your USB drive. Select it. The computer will boot from the USB drive instead of the hard drive, and the Windows installation will begin. A blue screen will appear with the Windows logo and the message "Windows is loading files".
If you miss the boot menu window, the computer will try to boot normally, fail, and either show an error or restart. Power it off, wait five seconds, and try again. You have a few seconds to catch that boot menu prompt, so watch the screen closely.
Walking through the installation screens
The Windows installer will ask you a series of questions. First, it asks what language you speak and what time zone you are in. Then it asks you to read and accept the Windows license agreement — a long legal document. You must click "I accept" to continue.
Next, the installer asks which drive you want to install Windows on. On a new PC with one drive, there is usually only one option. On a PC with multiple drives, choose the one you want Windows on — usually the fastest one, which is often labeled as the C: drive. The installer will erase everything on that drive, so make sure you are choosing the right one.
The installer then copies files to your drive, installs drivers (software that lets Windows talk to your hardware), and restarts your computer several times. This is normal. Do not turn off the computer during this process. The whole installation takes 15 to 30 minutes depending on your drive speed.
Setting up your user account and entering your product key
After the installation finishes, Windows will ask you to create a user account. You choose a username and a password. This is the account you will use to log in every time you turn on the computer. You can create additional accounts later for other people.
Windows will then ask for your product key — a 25-character code that proves you own a license to use Windows. This code usually comes in an email if you bought Windows online, or on a card in the box if you bought it in a store. If you have a product key, type it in. If you do not have one, you can skip this step and enter it later.
If you skip the product key now, Windows will still work, but you will see a watermark on your desktop saying "set up Windows" and you will not be able to change your background, lock screen, or some other settings. You can enter the product key at any time later to remove the watermark and unlock those features.
Connecting to the internet and installing updates
Windows will ask if you want to connect to a Wi-Fi network or use a wired connection. If you have an ethernet cable plugged into your computer, Windows may already detect it. If you are using Wi-Fi, select your network name and enter your password.
Once you are connected, Windows will check for updates — patches and improvements released since the installation file was created. This can take 10 to 30 minutes depending on how many updates are available and your internet speed. Let this finish. Do not turn off the computer or disconnect from the internet during updates.
After updates finish, your desktop will appear and you can start using your computer. You can now install programs, create files, and do everything else a computer normally does.
What to do if something goes wrong during installation
If the installer stops responding or shows an error message, the most common fix is to restart. Power off the computer completely, wait 10 seconds, and start over from the beginning. Plug in the USB drive, power on, press the boot menu key, and select the USB drive again.
If the installer says "No bootable device found" or "Boot failed", the USB drive may not have been created correctly. Go back to a working computer, create the installation media again using the Media Creation Tool, and try once more.
If the installer says your drive is not compatible or cannot be found, your drive may be failing or your BIOS (the computer's lowest-level software) may need an update. This is rare on new PCs. If it happens, contact the PC manufacturer's support line with the exact error message.
Frequently Asked Questions
Do I need a product key before I install Windows?
No. You can install Windows without a product key and enter it afterward. Windows will work either way during installation. If you do not have a key, you can still use the computer — you just cannot customize certain settings until you add the key later.
Can I use the same USB drive to install Windows on multiple computers?
Yes. The USB drive is just a copy of the installation file. You can use it on as many computers as you want. Each installation needs its own product key to be fully activated, but the USB drive itself can be reused.
What if my new PC does not have a USB port?
Some very new or very small PCs may only have USB-C ports. You can use a USB-C to USB-A adapter, or create installation media on a USB-C drive if your working computer has a USB-C port. You can also use a DVD instead of a USB drive if your new PC has a DVD drive.
Will installing Windows erase my files?
Installing Windows on a brand-new PC will erase everything on the drive you choose, but a new PC has nothing on it yet. If you are reinstalling Windows on a used PC, back up your files first — the installation will erase them.
How long does Windows installation take?
The actual installation process takes 15 to 30 minutes. After that, Windows updates can take another 10 to 30 minutes depending on how many updates are available. Plan for an hour total from start to finish.