the DVD drive stopped working and now the hard drive has errors.

I got an external USB DVD drive on it, but chkdsk cannot seem to repair the hard drive.

Anyone got any idea how to fix it or recover data off of the hard drive. I got a year's worth of work on it, and none of my files show up. Just "File record segment XXXXX is unreadable" errors about a million of them.

Suggest you stop using the drive until you can recover the data.
It is likely that drive has failed or is going into total failure.
You can purchase a replacement drive for $42 to $75 depending on size and whether you get the 5400 rpm or the 7200 rpm in a 40, 60, or 80 GB model.
You can obtain an adapter to put the drive into a desktop unit as a slave. The adapter converts the mobile 2.5" hard drive by adapting the pin set for the desktop EIDE cable. Adapters are available many places, including www.geeks.com, www.cyberguys.com, www.frys.com, www.outpost.com, and others... cheaply at $2.45 to $9.99 depending on where you get one.
Then you can usually drag and drop the data from the mobile drive to a desktop drive, or use drive recovery software, then you can burn a CD to then migrate it to your new drive... or just use a USB transfer.
( We work on a great number of the Presario 2500's with identical problems. Did you know there are 434 different models of the Presario 2500 series of laptops?)
With the new drive, you just use the recovery set that came with your laptop, or buy the set for about $30, including shipping, from the Compaq parts department.
But you likely will not ever be able to use that drive again. Thus, you do not want to stress it further by more restart or rescue attempts.

I have a dell inspiron 6400

i need code it please help me

service tag:#HPV6t91-595B

Express Service Code:38569340053

please quick answer

You have posted that request in a thread for the Compaq Presario 2500 laptop series. Your post is irrelevant to that post.
Please post your request in the correct way, by searching for Dell passwords,.
There are hundreds upon hundreds of posts regarding Dell Passwords. You will be expected to read through the library of posts to see what is possible. There have been many on the Inspiron 6400...

Is it possible to get the data off of the drive? I have a year's worth of work on it, and didn't back it up. I have backup data from over a year on another drive. Using a BartPE boot disk I see that the NTFS system is damaged and my My Documents folder is gone, and sometimes it cannot even read the partition.

I'd put the drive in a desktop adapter if I knew how to remove it. I removed over 20 screws and it still wouldn't open up. Are there hidden latches or screws on the notebook? I can't seem to find them.

If I have to buy a new hard drive, I might as well buy a new laptop. This thing is a Pentium 4 with Windows XP Home Edition. I can get a Vista Premium Laptop for $500 easily. This thing originally cost $1299 in 2003, and worked great until the hard drive failed.