A+: If your Win7 Install Goes Wrong

If the system won’t start, you can still view log files. However, this depends on the type of installation and how far the installation got. If it was a clean installation, you should boot to the Windows 7 DVD; select Repair your computer, then access the System Recovery Options menu, and select the Command Prompt. If it was an upgrade that didn’t get far, and if Windows Vista/XP/2000 was previously installed on an NTFS drive, you can boot to the System Recovery Options in Vista, or the Recovery Console from a Windows XP or 2000 CD and view the log files from there.

 If you cannot start the clean installation or upgrade, check the following:
• Processor speed and memory size: Verify that your computer meets the minimum requirements for Windows 7.  Make sure you are installing the correct type (32-bit or 64-bit) and version of Windows 7.
• Windows type and version: Make sure you are installing the correct type (32-bit or 64-bit) and version of Windows 7 (Starter, Home Premium, and so on...).
• Free disk space: You need 16 GB/20 GB free for Windows 7 (for 32-bit and 64-bit editions respectively); the more space available, the better.
• Hardware conflicts or hardware issues: Use the Device Manager to ensure that all hardware works correctly before you start an upgrade.
• Installation media: Make sure that your DVD-ROM media is not scratched or damaged in any way. Verify that it is genuine Microsoft software and that you have the right type of media for your installation, for example, Windows 7 Full Version License or Upgrade DVD.