I generally feel better, and your explanation does help, but it is still not crystal clear exactly what is where.
Is there any change of the photo of the computer and nearby speaker, or a simply sketch to give us a more visual representation?
To give you a general sense of how distance can make a difference, let me relate my situation. I have some larger 12" woofers with 32 ounce magnets. At my old house, they sat a little higher than they do now. This place them beside my TV (CRT), near the bottom right corner, and I did get screen aberrations cause by the effects of the magnets.
In my new house, the speaker was still next to the TV, just on a different stand that placed it a little lower. The straight line distance of about 10" to the magnet was about the same, but it was now down and to the right. In this case, no problem with magnetic interference. So, subtle changes in the location can make big differences in the result.
Also, keep in mind that your computer cabinet represents a shield, and the hard drive itself is further shielded pretty substantially. So, you have a degree of protection.
So, my point is, very fine and subtle details make a big difference, so a photo or sketch could tell us a lot.
PS:
Have you used the speakers yet, and what is your impression of them? Always valuable information.
Steve/bluewizard