I am building a computer and want to use Windows XP
professional for the operating system. Shopping around I
find an OEM version of the program and a regular version.
Besides price what are the differences.
In any case, you will be unable to use an OEM version to
upgrade a previous operating system, since OEMs must be installed
"clean", on a freshly-formatted HD. This means that you will
lose all your currently-installed software and settings, unless
they are backed up on an external HD or CDs.
"Full OEM" versions usually have everything a normal "Retail"
CD has, except, of course, code which allows for upgrades. I did
find a variance between my XP Home Edition "Full OEM" CD and my
XP Professional "Full OEM" CD -- while the Home Edition CD had
a folder containing Backup on it, Professional did not.
If you don't mind installing your OS "clean" each time, and
don't need Microsoft support, "Full OEM" versions can be a
tremendous value, since they are usually up to $165 less than
a Full Retail version.
However, if you can afford it, purchase an Upgrade version,
if you have a previous version of Windows. It is the better
value, since it can do either an upgrade or a clean install,
for $100 less than a Full Retail version, which can also do
either an upgrade or a clean install.