Imagine your system as a competent, fair minded person sitting at a desk, juggling mail, requests, complaints, reports, faxes, memos, deciding what to deal with first, what to answer, what to leave for later.  Now imagine yourself as that person's boss.  You come along and tell them that the normal procedure has changed for the moment... you tell them what to respond to first, what will get priority until you say otherwise.

Windows XP has a handy option that can be made to show up in a context menu when you right-click a program's main executable or a shortcut to that file, or when you right-click a Process in the Task Manager.

<Task Manager is the panel that appears when you use the key combo CTRL+ALT+DEL or CTRL+SHIFT+ESC, when you type taskmgr in the Start Menu's Run... box or a command prompt, or when you right-click the taskbar and select Task Manager.  Once in Task Manager, click the Processes tab to see what's running, then right-click an item and choose Set Priority to see what that item's status is.>

<--Another note: I made a mistaken assumption that Start High Priority was available in a program/shortcut's right-click menu by default, but after an XP reinstall, I noticed it wasn't there.  Later I found out that I put it there, that is I told X-Setup to do it.  Then I found (here) the instructions for getting X-Setup to do it again.  Here are the steps, slightly modified from the original:
    - "...Get Xteq XSetup
    - Install it, run it and navigate to System -> Advanced Performance Settings
    - Click to select "Enable command on context menu for EXE files"
    - You'll now notice a new option called "Start High Priority" in the context menu when you right-click on any executable..." (or on its shortcut, whether from the Desktop, from Windows Explorer, or from the Start Menu)-->

When you give high priority to an application in Windows XP, you're telling the system to give extra attention or preferential treatment to that program, which can help the program to write to disk faster, refresh faster etc., than it might at lower priority settings.

If you use Set Priority by right-clicking a Process in Task Manager, don't go any higher than High Priority.  I tried switching a program to Realtime and caused a total Windows XP lockup, one of only two or three since I started using XP.  It's also better to give only one application High Priority at any one time, especially on a slow machine.

To set a program to High Priority, I prefer to right-click a program or program shortcut from the Start Menu, the Desktop, or Windows Explorer, rather than use the Processes tab in Task Manager.  That way, I get to launch the app and give it High Priority in one click.  One drawback, however, is that there is only one priority option in the right-click menu, Start High Priority.  But maybe that's the only setting needed... it's definitely the only one I'm after.  Another disadvantage is that startup switches are ignored.  For example, I have a Mozilla shortcut set up to launch with a switch called -nosplash (lets you bypass the splash screen).  If I right-click it and choose Start High Priority, that switch is ignored, along with any other option I might care to put there, like -edit which would normally launch Mozilla in page edit mode.  A way around the problem, is to set priority levels at the command line, which lets you include other switches as well.  See below.

Here is another way to start a program and give it high priority at the same time.  It requires the command line and that you know the exact location or path of the program to be... prioritized.  ... an example:
    This one should work if you have Word or Office 2000, and if Word's main executable is at "C:\Program Files\Microsoft Office\Office\"
        - Start Menu / Run... / type CMD / press ENTER
        - type cd /d "C:\Program Files\Microsoft Office\Office\"
        - type start /high winword.exe

For long paths it's a pain, I know.  A batch file can help out, one like this:

@echo off
cd /d "C:\Program Files\Microsoft Office\Office\"
start /high winword.exe

If I wanted to use a batch file to run the Mozilla page editor in High Priority mode, and without the splash screen, the lines would go like this:

@echo off
cd /d "C:\Program Files\Mozilla"
start /high mozilla.exe -nosplash -edit

<Note: The above path is not the default folder that Mozilla creates during installation.  I chose this one because I already know that Mozilla.org is behind the software and I don't need a clunky looking folder name to be reminded of that.>

There are other examples, some with shorter paths, as you'll see if you go that route.

< For more on batch files, visit Gord's World of Batch Files and become a member of the free Batch World mailing list.
Still more info on batch files can be found here:
    - Using batch files (Microsoft)
    - Batch File Commands (Windows Support Center)
    - Information On Batch Files (Computer Hope)>