Had a problem with the monitor that came with my recently purchased Dell 530N with Ubuntu. After a couple of hours, the monitor would get brighter and brighter until it reached maximum brightness and then after a few minutes of that, the lamp in the monitor would go out leaving me with a black screen. I could turn the monitor off for a few minutes (and presumably, let it cool) and it would work for another couple of hours.
I got tired of that (Hey! I'm trying to write a book here!) so I called Dell's Ubuntu support number (1-866-622-1947) and got connected to an overseas call center. The representative had me perform a simple test, reboot the computer and press F2 to get to the setup screen, then just let it sit and see if the monitor would fail again. This test would eliminate the possibility of a video driver issue. Sure enough, after about 30 minutes, it went out again. I called back and talked to another representative who was able to see what had transpired during the first call. She arranged for a replacement to be shipped overnight to me. A refurbished monitor arrived the next afternoon.
I'm pleased with the service. Their support staff was polite and professional, but I didn't have a chance to test their Linux skills.
Maybe next time.