ESATA ports on Dell E-Series portables is disabled when SATA Controller is operated in ATA mode

Unfortunately you are not alone on this matter. Most of what I am finding for the problem is software related. The general consensus is that the E6400 with Win XP has some big issues. Remove all of the pre-installed dell software, especially Dell Control Point, this is typically the cause of repeated bluescreens and frequent drops in Wifi and WLAN connectivity.

If that doesn't salve it you will have to get more technical. You need to be sure that the BIOS SATA Operations setting needs are changed from IRRT to AHCI because IRRT is supported in Windows 7 but not Windows XP.
Also check to see if the CD Drive is being recognized. If not check to see what version of BIOS, audio and video drivers are installed on the laptop. As of May 2010 - the latest versions for Windows XP Professional SP3 32-bit operating systems were as follows:

1. BIOS - A20 (E6400A20.EXE)
2. IDT Audio - 5.10.0.6274, A11 (R267815.exe)
3. Intel Video - 6.14.10.5029, A07 (A07_R212481.exe)

Dell reported they have had many cases with lockups and freezing on E6400's and the majority of the cases were resolved with updating the Intel Controller driver. Also, updating to the latest bios would be prudent if not done already. The system would need to be running either AHCI or IRRT Sata Operation in the bios to install this update though.

Go to http://www.intel.com/p/en_US/support/detect?iid=dc_iduu and click on the "Check your system for updates" button.

The other drivers you should be able to get from the dell website http://www.dell.com/support/troubleshooting/us/en/19/Product/latitude-e6400?~srd=true&sk=e6400&scat=sup

Double check the bois to ensure you have all the Sata ports turned on. I have found in some Dell computers the only ports turned on are the ones in use when shipped from the factory.

Try this hints:
1.Press F2 to enter BIOS on start up
2. Expand Drive section
3. Go to SATA Operation
4. Check and change from Raid Auto/ AHCI to Raid Auto/ATA

Good Luck

Frankly speaking, Vostro has many intermittent issue like slow start-up, application error during shutdown or restart. Sometimes it even crashed with our co antivirus, acrobat writer etc..

We have reported many cases to DELL but unfortuntely no fix solution. We have at least 5 machines out of 20 reported similar issue.

Tell you, the best is to upgrade to Latitude if you budget permit. No point wasting time on this.

Unofficially, dell engineer told our IT engineer that vostro has many problem and not really suitable for office use... that is why the price so cheap...

From my true heart. good luck!

Hi...

If your HDD will not recognized during installation you need to check if your HDD is detected. Try to look at your BIOS if it is detected. IF the HDD will not detected you need to replace the cable, try to use the other slot of your SATA or IDE ports.

Regards
ICmanServer