My dvd writer cannot read DVD-Video Disc,but can write all dvds

Dear i have send a some information of your problem.
i have found some links please read this carefully.
and these links are help full of you.
Thanks.

The jerky pictures and poor sound quality are most probably caused by the IDE controller (the computer has an IDE hard disk drive) not being set to Direct Memory Access (DMA) mode, which allows the DVD drive to transfer data directly to the RAM memory instead of via the processor. The alternative mode is called PIO mode, which makes use of the processor. During a DVD movie, the processor's workload gets too heavy and the stress on it makes the video become jerky and the sound quality deteriorate.
The following article should contain all of the information you need to fix the problem.
DMA reverts to PIO - http://winhlp.com/node/10




First try playing different DVDs, preferably pressed DVDs instead of home-recorded DVDs, in order to make sure that you didn't just try to play a bad DVD.
Dell used to provide Recovery CDs with all of its computers, which it still does with its business computers. You can still buy the Recovery CDs as an option during the purchase of a home computer, but for the last few years, in order to cut costs, if the purchaser doesn't buy the CDs, Dell uses a recovery partition on the hard disk drive where all of the recovery files are stored. The recovery procedure is started from the command prompt, which you can open by entering cmd in the Start => Run box in Windows XP, and in the Start => Start Search box in Windows Vista.
It would be time-consuming and difficult to describe how to remove and reinstall the DVD decoder, so Dell's support suggested the easiest method of recovery from the company's point of view, and the worse method from your point of view. In any case, the problem might not even be software-related. It could easily be caused by faulty hardware. Sometimes, even though a drive can recognise and read CDs, a hardware fault could prevent it from recognising and reading a DVD.
That said, the cause of the problem is more likely to be software-related, so, I suggest using the Windows DVD Troubleshooter. To run it in Windows XP, click Start => Help and Support. Under Pick a Help Topic, scroll down to Fixing a problem and click on it. In the window that comes up find Games, Sound and Video problems, and in the right-hand window, click DVD Troubleshooter. To find it in Windows Vista, enter DVD Troubleshooter in the Search box of its Help and Support.
This MS Knowledge Base article provides other suggestions: How to troubleshoot common problems that may occur when a Windows XP-based computer cannot read a CD or a DVD - "This article describes how to troubleshoot common problems that may occur when a Microsoft Windows XP-based computer cannot read a CD or a DVD in a disc drive. This article contains several methods that you can use to try to resolve these problems." - http://support.microsoft.com/kb/321641
If you don't have the CD that contains the DVD decoder software, it might be difficult or impossible to locate. Usually, the DVD decoder software that comes with a DVD drive or PC has a condition of its licence that it can only be distributed with the DVD drive for which it is licensed, which means that it is not usually made available as a download. Fortunately, your PC uses Sonic Solutions software, which can be downloaded from Dell's Support site here: http://support.dell.com/.
You could also try using a free 30-day trial of Cyberlink's PowerDVD software from http://www.cyberlink.com/. It is generally regarded as being superior to Sonic Solutions software and the Windows Media Player. If you decide not to buy Cyberlink's PowerDVD and uninstall it after the trial period, it leaves behind the MPEG2 codec, which allows you to play DVDs using the Windows Media Player.
If the problem is hardware-related, you'll have to replace your PC's DVD drive. DVD drives/writers are currently very inexpensive, especially when compared to the prices of Blu-ray drives/writers.