depends on how much space your hard drive or solid state drive can hold.
A backup disc is usually not used for Windows itself or applications, but for personal data. Thus the amount of space needed depends entirely on how much space your files take up.
Well,you can use Windows Live messenger as mentioned.But also you can create your own profile on Windows Live AND you can create your own blog or your space,on Windows Live Spaces.
Windows Exporer
Windows
Yes, creating another account does use more disk space. Files and folders are created for the new account to function. Typically the size is only a few megabytes and at least the size of the Default User profile.
* The new aero interface * User Account Control * Windows Meeting Space, Sticky Notes, Windows Calendar, Windows DVD Maker, Windows Contacts, Windows Fax and Scan, Windows Sidebar, Windows Mobility Center,and Windows Journal * Welcome Screen * Windows Speech Recognition
20-40GB depending on version. https://www.microsoft.com/windows/windows-vista/get/system-requirements.aspx
Windows 7 required 20 Gigabyte (GB) of space to install a 64-bit version into the system.
A 20GB hard drive with at least 15GB free space.
During installation, Windows 7 will need about 16GB on a hard drive.
it depends on which one you buy
There is no root account in Windows XP. Nor is there an account that is a "superuser" account in the traditional sense.