How do I remove all the System Restore points except the recent one?

All the System Restore points can be cleared by disabling and enabling the System Restore option. This is discussed here. However, Windows XP provides an option to clear all the System Restore points except the very recently created point. This can be accomplished through the Disk Cleanup Utility in XP.

  Click Start, Run and type CLEANMGR and press Enter
  Select the hard disk partition and press OK
  At the top of the dialog, click the tab More Options
  Under System Restore section, click the button "Clean up..."

Now, all the System Restore points (except the recent one) are cleared and more hard disk space will be free.