Hi there Zyr0,
That is unpleasant.
I believe you can go to Disk Management and see how the flash drive appears over there. It would be nice to provide a screenshot as well.
If you are unable to reformat it through Disk Management, then I believe you can see if some brand specific tool would help. Most of the flash drive manufacturers have some partitioning/testing tools.
You don't have data stored over there right?
Keep in mind that the flash drive could have failed.
Let me know how this goes,
D_Know_WD