Thanks for posting back with some info.
This still sounds like a DMA issue.
Click on the first DMA link in my sig and follow Womble's guide..very straightforward.
If your problem persists, click on the next DMA link in my sig. There is a link to a script file that you can run. Before you do this, read over the text, a lot of good info there that will help you understand what's going on.
StormJumper has also got info (link) in his sig re: DMA. Some of the info may be repetitive, but he did a great job and have a look there as well.
Hope this helps.