The Notebook Review forums were hosted by TechTarget, who shut down them down on January 31, 2022. This static read-only archive was pulled by NBR forum users between January 20 and January 31, 2022, in an effort to make sure that the valuable technical information that had been posted on the forums is preserved. For current discussions, many NBR forum users moved over to NotebookTalk.net after the shutdown.
I don't think this is normal, but then again, I don't have a dv4000. A previous user posted a similar type of problem with their nx8220, seemed to have excessive flexing on the right side of the keyboard. I suggested to have the keyboard reseated as the keyboard may not have been instered correctly during manufacturing. Normally, notebooks have a few screws on the underside to have it release, but you may also need to remove a small bezel in order to get access to screws on top of the keyboard. Once all the required screws are out, carefully pull the keyboard off and then reseat it. If this doesn't fix the issue, then it could just be a lack of support under that area of the keyboard. You may want to look at inserting something (non-conductive) to support that area. Just be careful as any physical damage you do will void the warranty.
Problems? See this thread at archive.org.
