I got a T-Flash USB memory stick which supports MicroSD in the back and I've used it once to put some files on it then i left alone it for a long time maybe a few months. I tried to put it into the USB port and it was recognized then as i was transferring a file onto my microSD card it , halfway through it just stopped working. Then i kept o unplugging/plugging it back it and only once has it been recognized then it stopped working again. What's really weird is that Windows is reporting that aren't any drivers installed for my flash drive but also it's saying that the drivers for this device are up to date?.
You have MicroSD card , that is inserted into the USB stick, which is then inserted into the computer, correct? If so, I would try removing the MicroSD card and trying in another reader, either via a SD card then memory reader, or straight memory reader depending on what you have. But it sounds like the MicroSD card has gone bad, perhaps through some combination of age, storge, or mis/use.
edit: Make sure whatever card reader you are using is working, make sure it is recognized and other similar cards are usable. Also try both USB2.0 and 3.0 if you can, directly to the back of the computer, not through a front panel or card reader.
I'm sure it's not the microsd card because it works when i put it into my R4 Flash Cart and into my DS. I think it is the flash drive itself ; I only plugged it into the front port and it said 'Installing Device Driver' but then it fails and gives me error code 43. Nothing happens when i plug it into the port at the back.