Question : Problem: Added ram but computer does not run faster

My computer runs extremely slowly when working within, and going to/from, Windows XP. It is mostly running Microsoft Dynamics POS system, and the startup and shutdown of this program is slow as well.. It had 512mb ram, and I added an identical stick but it seems to make no difference. It is an HP rp5000(DK779AV) Intel Celeron CPU 2.5ghz, 1gb ram, 75g hdd, 13g used. XP service pack 3 (but ran the same with sp2).

The computer appears to be seeing the additional ram. Is there something I need to do to have it use it? Or is the slowness due to another issue?

Answer : Problem: Added ram but computer does not run faster

I agree. But I would see about nasties and turning off unneeded services, before adding more ram.
Check out these sites, and figure out what Services you can turn off:

A listing of the startup files, and to see if you need them or not.

http://www2.whidbey.net/djdenham/Uncheck.htm  
http://www.3feetunder.com/krick/startup/list.html

Un-needed services of your Windows 2000/XP
http://smallvoid.com/articles/windows-xp/services/

for XP
http://www.blackviper.com/winxp/servicecfg.htm

If Black Viper gives you a problem, try:
Copy of Black Viper Services list (What you can disable/Turn off)
http://majorgeeks.com/page.php?id=12  

Description of resources:
http://www.aumha.org/win4/a/resource.htm  

Description of Startup prog:
http://netsquirrel.com/msconfig/
http://www.answersthatwork.com/Tasklist_pages/tasklist.htm  

You can also use the Windows System Monitor to see how much ram is being used, to decide if more ram is needed.
Samurize is pretty good also
http://www.samurize.com/modules/news/