I FOUND THE ANSWER AT THE DISKKEEPER SITE
The Default (built-in) defragmenter does not return or function after uninstalling Diskeeper on Windows 2000/XP.
The uninstaller may not have restored the default defragmentation registry entry. Please use the steps below.
Note: in line 5, the string starts with C:. If you have Windows installed to a different partition, replace C with the letter of that partition.
Before you begin any editing of the registry, always remember to update your emergency repair disk (ERD).
1. Click Start, Run. Type "regedit" in the text box and click OK.
2. Under HKEY_LOCAL_MACHINE, double click SOFTWARE, then Microsoft, then Windows, then CurrentVersion, then Explorer, then MyComputer
3. Click DefragPath
4. In the right-hand pane, double click (Default). This will bring up and Edit String window.
5a. For Windows XP: Change the string to read "mmc.exe C:\WINDOWS\system32\dfrg.msc %c:" and click OK.
5b. For Windows 2000: Change the string to read "C:\WINNT\system32\dfrg.msc %c:".
Please Note: You may have your Windows 2000 or XP operating system installed to a different directory from the default of C:\WINNT (for 2000) C:\Windows (for XP). If so, modify the command above to reflect that correct directory location.
Please Note: The difference between the two lines above is that the Windows XP string begins with "mmc.exe", and the Windows 2000 string does not.
6. Close the registry.
7. Open the Command Prompt; To open the command prompt, click Start, point to All Programs, point to Accessories, and then click Command Prompt.
8. Type "CD \WINDOWS\system32" and press Enter. (the Note above applies here also)
9. Type "Regsvr32.exe DfrgSnap.dll" and press Enter.
10. A window will appear confirming the success of the registration; select OK.
You should then be able to use the included default defragmenter in Windows 2000 or XP.
Now select START\PROGRAMS\ACCESSORIES\SYSTEMTOOLS and right click on DISKDEFRAGMENTER, then click Properties. Change the Target box to:
%systemroot%\System32\dfrg.msc