Downloading an installer image is the easy part. The problems start when someone writes it to a USB drive, restarts their machine, and discovers that the BIOS will not boot from it, the partition format is wrong, or the installer hangs because Secure Boot is blocking an unsigned bootloader. After more than a decade of guiding people through this process, I can say with certainty that the preparation you do before downloading determines whether the install takes thirty minutes or three hours. Every step on this page exists because I have watched someone skip it and then spend an hour diagnosing the entirely predictable consequence.
The sections below cover system verification, storage preparation, BIOS pre-configuration, USB media selection and testing, and a final pre-download checklist that you can run through in about ten minutes. Getting these right means the actual install process - from download to working desktop - can be completed in a single focused session.
Before downloading anything, confirm three things about your machine: the processor architecture, the firmware type, and the storage controller mode. These three facts determine which image to download, how to write it, and whether the machine will boot from it. Getting any one of them wrong means starting over.
Processor architecture
Nearly all machines from 2008 onward use x86_64 (64-bit) processors, and the standard installer images target this architecture. The exceptions are a handful of early Atom-based netbooks that use 32-bit-only processors. On Windows, check System Information (msinfo32) - the System Type field will say either x64-based or x86-based. On Linux, run uname -m - you want to see x86_64. If your machine is 32-bit, you need a specific 32-bit image, which is noted in the download listings.
Firmware type - UEFI or legacy BIOS
This determines the partition format of the USB installer. UEFI machines need a GPT-formatted installer. Legacy BIOS machines need MBR format. Writing the wrong format produces a USB drive that the machine silently ignores at boot time - no error message, no feedback, just a boot straight to the existing operating system as if the USB drive does not exist. On Windows, check msinfo32 for the BIOS Mode field. On Linux, check for the existence of /sys/firmware/efi.
Storage controller mode
Enter the BIOS setup and confirm the SATA controller is set to AHCI mode, not IDE or RAID. IDE mode works but degrades performance and causes detection failures with some Linux kernels. RAID mode is used on some Dell machines by default and will prevent the Linux installer from seeing the internal drive at all. Changing this setting after Windows is installed can cause Windows to fail to boot - change it before starting the new OS installation, not after.
If you are installing to the machine's internal drive - whether replacing the existing operating system or setting up a dual-boot - the state of that drive matters. A drive with failing sectors will cause random errors during and after install. A drive that is nearly full may not have enough contiguous space for a new partition. These are problems you want to discover now, not halfway through an install.
Storage health and space checklist
- Check SMART status: On Windows, run CrystalDiskInfo. On Linux, run
sudo smartctl -a /dev/sda. Look for reallocated sector count, pending sector count, and current pending sector values. Any non-zero value on these indicators means the drive is failing. Replace it before installing anything. - Check available space: A lightweight Linux installation needs 8 to 15 GB depending on the distribution. If dual-booting, you need that space as unallocated or on a partition you can safely shrink. Windows partition shrinking works in Disk Management but often leaves less free space than expected due to unmovable system files.
- Consider a drive swap: If the machine still has a mechanical hard drive, this is the ideal time to swap it for an SSD. The difference in boot time is dramatic - typically from 60+ seconds to under 20. A 120 GB SATA SSD is inexpensive and transforms the usability of any machine from this era.
- Back up everything: A fresh install overwrites the target partition entirely. Dual-boot installers are generally safe with the correct settings, but mistakes happen. Copy your personal files to an external drive before starting. A full disk image with Clonezilla gives you a complete rollback path if needed.
The USB drive you use for the installer matters more than most people expect. A drive with failing flash cells produces write errors that result in a corrupted image - and the symptoms look identical to a bad download. I have seen people re-download an ISO three times before realising the problem was the USB drive, not the file.
USB drive requirements
- Capacity: At least 4 GB, preferably 8 GB. Larger images and multi-boot tools like Ventoy work better with more space.
- Health test: Before writing, do a full format (not quick format) to scan for bad cells. On Windows, uncheck Quick Format in the format dialogue. On Linux, use
badblocks -wsv /dev/sdX(this is destructive - it overwrites everything on the drive). - Write speed: Slow drives extend the write process but do not affect the final result. If writing takes more than 15 minutes for a 2 GB image, the drive is very slow but not necessarily defective.
- Port compatibility: Test the specific USB port you plan to boot from. Some older BIOS firmware cannot boot from USB 3.0 ports in legacy mode. If boot fails, try a USB 2.0 port before troubleshooting further.
Once you have a verified USB drive and know your machine's firmware type, writing the installer image is straightforward. Use a dedicated image writing tool - do not simply copy the ISO file onto the drive.
Rufus (Windows)
The most reliable option on Windows. Select the ISO file, confirm the target drive, and choose the partition scheme: GPT for UEFI machines, MBR for legacy BIOS. Rufus will handle the rest including filesystem selection and bootloader configuration. Use the latest version - older versions have bugs with certain ISO formats.
Etcher (cross-platform)
Simpler interface, fewer options. Select the image, select the drive, click Flash. Etcher writes in GPT format by default, which works for UEFI machines. For legacy BIOS, Rufus or dd may be more reliable. Etcher includes a built-in verification step after writing.
dd (Linux/macOS)
Maximum control, no safety net. The command is sudo dd if=image.iso of=/dev/sdX bs=4M status=progress. Triple-check the target device - dd will happily overwrite your system drive if you point it at the wrong device. Use lsblk to confirm the USB drive's device name before running the command.
Confirm before downloading
- Processor architecture confirmed (64-bit or 32-bit)
- BIOS/UEFI mode identified and noted
- SATA controller set to AHCI mode
- Secure Boot status checked (disable for unsigned images)
- Internal drive SMART status verified healthy
- Backup of personal files completed
- USB drive tested and formatted
- Image writing tool installed and ready
- Second device available for troubleshooting reference
With these checks complete, you are ready to download. The downloads section has the installer images with version notes and checksums. The system requirements page has the full hardware compatibility reference if you want to verify specific chipset support before committing.