Windows 7 Overview

Windows 7 keeps the good and tries to fix the flaws
    Speed: Windows 7 offers “faster, more responsive performance.”
    Hardware: The standard edition requires 1 gigabyte of memory and 1 gigahertz processor; more is better.
    Nagging: Unified Action Center.

How to prep for the XP to 7 Upgrade
    Windows 7 Upgrade Advisor
    Windows 7 Compatibility Center
    Make a disk image of your XP machine
    Backup your data files
    Find all of your applications software install disks/download sites
    Install Windows 7
    Reinstall all the software you plan to run on Windows 7

Things you need to know
    Upgrading from XP on the same hardware will be tricky
    Virtualization allows XP on Win 7
    Go for 64-bit

Other useful sites

Windows 7 a complete survival guide

HP and Windows 7

Windows 7 Help & How to

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