Upgrade to Window 8.1 from Windows Vista

You would have to do a marathon upgrade by first upgrading to Windows 7, then to Windows 8.0 then to Windows 8.1

• Windows 7 Home Premium (x86)

• 32 bit

• Windows 7 Home Premium (x64)

• 64 bit

• Windows 7 Professional (x86)

• 32 bit

• Windows 7 Professional (x64)

• 64 bit

• Windows 7 Ultimate (x86)*

• 32 bit

• Windows 7 Ultimate (x64)*

• 64 bit

You will need to do a keyless installation (skip entering the product key and complete the installation).

32 vs 64 bit

http://windows.microsoft.com/en-US/windows7/32-bit-and-64-bit-Windows-frequently-asked-questions

Is my PC running the 32-bit or 64-bit version of Windows?

http://windows.microsoft.com/en-us/windows7/find-out-32-or-64-bit

http://windows.microsoft.com/en-US/windows7/Installing-and-reinstalling-Windows-7

ImgBurn - In addtion to supporting the creation of CD's from .ISO files,

it supports a wide range of other image file formats, and it's free.

(BIN, CUE, DI, DVD, GI, IMG, MDS, NRG, PDI and ISO)

http://www.imgburn.com/

http://neosmart.net/wiki/display/G/Burning+ISO+Images+with+ImgBurn

Note: Always use the slowest burn speed (4x or 2x) if offered a choice.

When making significant changes to your computer such as an upgrade, it is always recommended you backup your system prior to installing a new version of Windows. In your case, you can upgrade to Windows 7 depending on edition and architecture of Windows Vista you have installed. If you are running a 32 bit version of Vista and want to upgrade to a 64 bit version (edition of Windows 7), you will have to a do clean install, this applies vice-versa.

If you are running consumer editions of Windows Vista such as Home Basic or Premium, you can only upgrade to either Windows 7 Home Premium or Ultimate. Also, you cannot do downgrades, which means, if you are running Windows Vista Ultimate now, you cannot downgrade to Windows 7 Home Premium. You must do logical upgrades:

Windows Vista Home Basic > Windows 7 Home Basic, Premium or Ultimate

Windows Vista Home Premium > Windows 7 Home Premium or Ultimate

Windows Vista Business > Windows 7 Professional, Enterprise or Ultimate

Windows Vista Enterprise > Windows 7 Enterprise

Windows Vista Ultimate > Windows 7 Ultimate.

After upgrading to Windows 7, you next need to upgrade to Windows 8:

http://dellwindowsreinstallationguide.com/download-microsoft-windows-and-office/download-microsoft-windows/download-windows-8-1-iso/

After upgrading to Windows 8.0, you can then upgrade to Windows 8.1