A couple of things you might double-check are the type of USB port you're connecting to on the computer, as well as the type and length of the USB cable you're using.
Most computers have multiple USB ports, and sometimes they include two types-- USB 2.0 ports and USB 3.0 ports. I think the Akai might prefer one over the other-- probably USB 2.0-- so if your computer has more than one USB port, try connecting the Akai to different ones to see if it works with any of them.
As for the USB cable, using a cable that's 10 feet or longer might cause problems due to how long it takes the MIDI data to travel along the cable-- even though the data moves very quickly in human terms, to a computer even a very miniscule difference in timing can through off the keyboard's ability to sync with the computer. I know that Yamaha always says not to use USB cables exceeding 3 meters (which is about 9.8 feet I think), and that might be true for other brands as well, so I would stick with a USB cable that's 9 feet or less in length. However, the type of cable-- USB 1.1, 2.0, or 3.0-- might be even more significant that the length. Even though USB 3.0 has been around for a while now, a lot of USB-MIDI equipment seems to require or prefer USB 2.0 cables, and might not work with USB 3.0 cables.
Of course, if the Akai came with a USB cable, then that would probably be the best one to use. However, both data cables and power cords can become damaged by coiling and uncoiling them; the wires inside the cable or cord can become bent over time and eventually break. If you've kept the USB cable all wound up, it might have become damaged, so try using a different cable to see it that helps.
Aside from those ideas, check to see if there are any firmware updates available for the Akai, as well as any Windows updates available for the computer. Sometimes an update will cause a problem rather than fix a problem, which was why I asked earlier whether you'd updated anything on the computer. But if a Windows update causes a compatibility problem with a piece of equipment, the manufacturer of the equipment will often (but not always) put out a new driver or firmware to correct the issue.