Mr. Fixit's PC Upgrade and Repair
Windows 7
Windows XP users planning to upgrade to Windows 7 must perform a
clean install. Windows XP is not compatible with Windows 7. Back up all
of your programs and data, install Windows 7,  then reinstall your
programs and data.  XP users can use 'Dual Boot' as an alternative.
Windows Vista/ Windows 2000 users can either upgrade your existing
version to Windows 7 or perform a clean install. When upgrading Vista,
you can only upgrade to same version of Windows 7. For example, Vista
Home Premium can only be upgraded to Windows 7 Home Premium,
otherwise a clean install or dual boot is required.
Minimum System Requirements
32-bit Windows

1GHz  32-bit (x86) processor
1GB of system RAM **
16GB available Hard disk space
DirectX 9 with WDDM 1.0 support or higher
DVD/CD drive
Other requirements to use certain features:

Some features of Windows Media Center requires a TV-Tuner and other hardware.
Higher performance Graphics card
To use HomeGroup ALL PCs must use Windows 7 and connected to a network
BitLocker requires Trusted Platform Module v1.2 (Win7 Ultimate only)
BitLocker-to-go requires a USB Flash Drive (Win7 Ultimate only)
Auto back-up (Win7 Pro and Ultimate only)
WinXP Virtual mode (Win7 Pro and Ultimate only)
64-bit Windows

1GHz 64-bit (x64) processor
2GB of system RAM **
20GB available Hard disk space
DirectX 9 with WDDM 1.0 Support or higher
DVD/CD drive
**NOTICE**: Regardless of the maximum memory BIOS supports, ALL 32-bit
OS supports up to 4GB, Home Basic 64-bit version supports up to 8GB, and
Home Premium 64-bit version supports up to 16GB.  Professional,  Enterprise,
and Ultimate 64-bit versions supports up to 192GB.
hardware and software compatibility that caused Vista's downfall.  Microsoft made further advances in Windows Aero adding the ability to pin programs to the taskbar and
new Windows Managment features.  Advances in Touch and handwriting recognition, support for multiple heterogeneous graphics cards from different vendors installed in the
PC,  new version of Windows Media Center, and supports real-time multimedia applications for video playback and 3D games.  Libraries was added for better file
management.  Home Group was added that allowed all the computers on the home network to securely share files and printers between them.  Windows 7 recognizes
Solid-State Drives uniquely and can use the TRIM command by telling the SSD which memory blocks are no longer needed.   This ability reduced write-amplifications by
allowing the SSD to know which memory blocks are available for reuse after a file was deleted.  Windows 7 replaced Photo Gallery, Movie Maker, Calender, and Mail with
Windows Live branded versions that was part of the Windows Live Essentials.

Service Pack 1 was released in 2011 to add support for Advanced Vector Extension (AVX), which is a 256-bit instruction set, for Intel Core i3, i5, and i7 processors based on
Sandy Bridge and AMD FX processors based on Bulldozer. Resolved a bug in the HDMI audio and XPS printing.  The Service Pack also violated a 2009 ruling by the
European Union that forced Microsoft to remove Internet Explorer and provide a bowser ballot box so the user can choose their preferred Web Browser.  The Service Pack
removed the Ballot Box and installed IE.  In 2013, EU fined Microsoft  $623 million in an effort to deter companies from retracting on settlement promises.

Windows 7 received favorable reviews by many people noting that it was a major improvement from Windows Vista.  Windows Update cleanup (from Windows 8.1) was later
added as part of Disk Cleanup to remove outdated Windows updates and free space on the hard drive.  By March 2010, 90 million copies were sold and jumped to 150 million
in June 2010, making Windows 7 the fastest selling operating system in history.  Windows 7 was sold at the rate of 7 licenses every second.  By 2014, Windows 7 had a
market share of 47.49% that rivaled Windows XP's market share of 29.23%