In XP Pro, in order to get your uptime you must execute the SYSTEMINFO command at the CMD terminal.
As you know, this produces other system information output, and you have to scroll up to see your uptime.

If you wish to receive ONLY your uptime information, simply copy and paste the following into notepad

@echo.
@systeminfo | @find "System Up Time:"
@echo.

And save as UPTIME.BAT (save to your windows dir if you want to be able to access it anywhere)

Now when you type UPTIME you will see just:

---------------------------
System Up Time: 5 Days, 20 Hours, 13 Minutes, 46 Seconds
---------------------------

Also, if you wish to create a shortcut to IP.BAT, or run it via the Run command, it may close before you can view the result
To stop this, add @pause after the last @echo. command, this will cause the terminal to wait for your response before closing.

Example:

@echo.
@systeminfo | @find "System Up Time:"
@echo.
@pause

will result:

---------------------------
System Up Time: 5 Days, 20 Hours, 13 Minutes, 46 Seconds

Press any key to continue . . .
---------------------------

enjoy!

(information about the code: @echo. produces a blank line, @systeminfo | @find "System Up Time:" causes the output of systeminfo to be piped to the find command, which looks for the line containing "System Up Time:", find then outputs your system uptime, the optional @pause causes the terminal to wait for user input before continuing. The @ before each command tells the terminal not to echo the command being typed.)