Ok, after a lengthy delay in having time to mess with this, I applied the updates, but in a slightly different way: (I noticed that the version numbers directly on the Dell drivers site were newer than the shortcut links originally provided, and in fact, one update was dated just a few days ago). I applied those updates, rather then the ones you provided, Sundeep.
A couple observations and questions:
Question: In Device Manager, none of the obvious hardware items match the version number reflected in the website. For example, the"Intel series/C200 chipset family usb enhanced controller - 1C26" shows driver versino 9.2.0.1013, but the driver download indicated 9.2.0.1019. Is that just a byproduct of how the chipset drivers are?
Question: I have more mouse delay after the update than before, which is odd. (Both via the monitor's USB hub, and plugged directly into the machine). I may revert via System Restore, I haven't decided yet.) Any ideas on that?
Observation: I went 25 days (from my original post until yesterday) without a problem, plugging the keyboard/mouse into my monitor. The only problem I had, was the mouse had one failure, but the keyboard did not fail at the same time, so perhaps all these problems are a mouse going bad? (I can't say I've seen a corded mouse go bad electrically before, but that doesn't necessarily mean anything). I brought in two old mice from home, one an aincient PS2 mouse (should all my USB ports go bad, and another older USB mouse.. I'll add that to my troubleshooting research).
Thanks again for the help.