Hi Chris and Andrew,
I also agree--when Korg says the MR-1000 does not need a driver, they probably mean that they don't issue a special driver for the unit.
Chris, I found the Driver Files Detail and opened it for a mysterious "USB Mass Storage Device", but the information details are cryptic such that I couldn't conclusively link it for sure to the Korg. There is an option to see if Drivers are working, and all of them are reported as functioning.
Andrew, all I can say about the operating system is that it's Windows 7 Home Premium, and when I bought the Dell four years ago, Windows Updates started automatically when I first turned on the PC up to today. I've also gone manually into Microsoft Updates to see if anything should be downloaded. Right now there is one important update available for Skype, which I never use, and three optional updates that would provide no benefit to my use. So, yes, I do keep tabs on that.
Now, suspicion might be shifting! Yesterday we visited our son who also lives in Maine. I brought the Korg and USB2 wire with me. We turned on the Korg, switched to USB Slave Mode and plugged the wire first into a laptop running Windows 8. The Korg was not detected. Then we hooked it into a PC running XP. Again the Korg was not detected. Finally (the best test matching the same operating systems) we hooked it to a laptop running Windows 7 Home Premium. It took four tries, but on the last one the upload box popped up as it should. But I still can't achieve that at home. We surmised this: Both computers run Windows 7 Home Premium. Both subscribe to automatic Windows Updates, so both get the very same updates. Yet one worked (after a few tries), and one didn't work. Plus it didn't work in XP or Windows 8 either. This might suggest that there is a factor of intermittent performance present. For example, if an electronic component is now faulty of failing after seven years of use, it could be intermittent where sometimes it works and sometimes it doesn't. I just gave it a few hard taps to see if it would "blink" in some way, but nothing happened. This theory assumes that the problem is really the Korg. This might also raise questions about the retailer's tech being unable to make it fail. It has given me seven years of good service. Plus maybe the flash cards are better technology now than the older hard drive in the Korg. So maybe the best bet now is to open a search for a new recorder that will satisfy my needs for making home recordings.
P.S. The search is on already. I'm considering the Roland-Edirol R-44 and the Tascam HD-P2. One thing I noticed in comparing specifications is that the Tascam has a retake button which allows you to do a redo a take with a single button press. The old Korg involved several steps to do that. Hey, stop laughing!