Ok, for anyone that finds themself with this issue, I have solved the problem on my HP Pavilion dv5030us, and can tell you what is wrong (see "To ensure that this is your problem"). Also, (see "Solution") I describe how I was able to resolve the problem.
My story: I was streaming music from the internet one afternoon, and decided that I wanted to listen to music on my hard drive. I paused the track online and opened a track on the drive. All of a sudden, the whole system ground down to a crawl, the music was choppy and cutting out. When I would track the mouse around on the screen, it would stick in a similar "choppy" manner (though it was never unresponsive). I noted that the mouse and music would skip when the hard drive light on the machine would flash (my first indication). I ran all the usual diagnostics (virus, adware, hdd, defrag, S.M.A.R.T, etc), but did not turn up anything. I found a couple posts indicating that the problem could be direct memory access (DMA) settings from the hard drive. This turned out to be the case as my machine had switched the channel on which the hard drive is to Processor IO mode (PIO).
To ensure that this is your problem: start (-> settings) -> control panel -> system -> hardware tab -> device manager -> IDE ATA/ATAPI contollers
At this point, you will need to know which channel your drive is on (for the HP Pavilion dv5000, the default is the primary IDE channel). Double click the channel that your drive is on -> advanced settings tab. One of the devices here is your HDD (dv5000 default is device 0). The transfer mode should have "DMA if available" selected. Further, if you are having this problem, the "Current Transfer Mode" probably says "PIO only," which means that your processor is handling all IO accesses to the hard drive (and thus wasting many resources). The "Current Transfer Mode" should be something like "Ultra DMA Mode 5" (direct memory access (DMA), memory is directly accessed by the hard drive rather than controlled by the processor).
Solution: In order to fix this problem, I repaired my Windows XP installation using the installation CD. This forced the IDE channel driver to be reinstalled. Upon next boot, when I checked the "Current Transfer Mode" of the primary IDE channel device 0, it had been changed to "Ultra DMA Mode 5" instead of "PIO only". You might also be able to solve this by reinstalling the IDE channel driver.
This post has been edited by jthestness: 23 June 2008 - 12:55 AM