For the past several days on turning on the computer, running windows XP, it begins to run CHKDSK on my slave drive, D.  Why would it do that and How do I stop it from starting up each time?  Thanks so much!Properly shut down your computer the next time you power off.From time to time, mine does this for no apparant reason.  Only explanation:  It's Windows.MalikTous said on another post which MIGHT help:

Open your MSDOS.SYS file in Notepad (you may have to go into your Windows Explorer, Tools, Folder Options, View tab and disable all file, folder, and extension hides to get to it, then uncheck the Hidden and Write Protect check boxes in the right-click Properties of the file to edit it). It should have the line  

Autoscan=  

and an option number. 0 prohibits automatic ScanDisk on error reboot, and 2 allows automatic ScanDisk on error reboot only. Change the number, I recommend 2.From the XP Help and Support (START Menu)

SUMMARY
When you run the command CHKDSK /F /R from the command line, Windows asks if you want to schedule CHKDSK to run the next time the system is restarted. This article describes how, in the event you choose YES, you can subsequently prevent CHKDSK from running the next time you start the server.
RESOLUTION
To stop the execution of CHKDSK /F /R, you must edit the registry using Registry Editor.

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

To stop the execution of CHKDSK /F /R, take the following steps: 1. Run the Registry Editor(Regedt32.exe).  
2. Under the HKEY_LOCAL_MACHINE subtree, go to the following subkey:
\SYSTEM\CurrentControlSet\Control\Session Manager
3. Change the BootExecute entry from:

autocheck autochk * /r\DosDevice\C:

To:

autocheck autochk *
If you have scheduled CHKDSK for MULTIPLE volumes, there will be an autocheck entry for each volume. Delete the string from the BootExecute registry value for each volume you do not want CHECKED.

This procedure will reset the default string, and CHKDSK /F /R will not run on reset.

Hope that this help you.
Alternatively try Diskeeper 9 Professional's Frag-Shield and see if your Master File Table on that drive is big enough.

I had to pad out the MFT on one of my drives recently. As raptor has stated and over missed by PEOPLE again ...whossh...shutdown the pc properly...windows will  execute the disk checker program  on startup witch is linked to the system file checker program it does this to check if there have been any alterations to the auto exe bat /boot ini files...to turn of a pc  start/run shutdown... Quote

From time to time, mine does this for no apparant reason.  Only explanation:  It's Windows.