How to export and import environment variables in windows?

I would use the SET command from the command prompt to export all the variables, rather than just PATH as recommended above.

C:\> SET >> allvariables.txt

To import the variablies, one can use a simple loop:

C:\> for /F %A in (allvariables.txt) do SET %A

You can use RegEdit to export the following two keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

HKEY_CURRENT_USER\Environment

The first set are system/global environment variables; the second set are user-level variables. Edit as needed and then import the .reg files on the new machine.