As a test for some clients we'll boot up Linux off USB (no need to install) and see it happening there.
Alienware keyboards tend to be closer to 99USD so you can imagine the owner usually wants to debate if it's the keyboard. This is why we try the other OS and USB keyboard tests.
I have a Alienware 17 R4 that I picked up and had to let it sit for more than a year as I suddenly had to take care of a sick relative (bye bye warranty). I finally got around to use it and found that the #4 key on the number pad acts like it is being pressed repeatedly. Most often this will cause the cursor to move left thanks to number lock usually being on.
I removed the key to see if something was stuck, but it looks fine. The issue also doesn't seem to be constant either. It is a problem when I try to use things like Word, doing a Google search, or am just trying to power off using the start up button. If I go into a game that makes use of the number pad, it doesn't seem to be an issue though. I can even use the key to type a 4 or to move left. The games don't seem to treat it like it is being repeatedly pressed or held down. This is for games that it is difficult to actually log into if they require a password when launched due to the cursor constantly trying to move left. Another strange aspect is that it doesn't seem like the key is being triggered at a constant rate. Some times I can manage to type something like a simple google search, but other times it's almost impossible.
I don't know if this is a hardware or software issue. I am running Windows 10. All my own research only turns up articles on stuck keys. Has anyone encountered an issue like this before?