OK. If you do not have the technical training or expertise to do this, you need to try it in a test environment first. Mass deployment requires working knowledge of sysprep and Windows Automated Installation Toolkit. The upgrade path from XP to Windows 7 is also not viable, but a Windows 8 path is. You need to look into this more in the technical articles I posted above, as this may require a great deal of time and organizational cost to your business. It may be such a pain, that if you do not want to use an automated method, you could do it one-by-one manually. In almost every automated instance, this will require your systems to be completely networked with either a Windows Server or master computer to roll out the updates.