I wouldn't worry about those being modified by malware. The drivers themselves aren't malicious, but ESET must have (recently?) been aware of a way to use these drivers in a malicious way (as in they are possibly vulnerable), and is blocking them to play it safe. Also, it only seems to care about the NVFlash utility's drivers themselves, and nothing with the BIOS files of your old GPU.
As for why this happened out of nowhere, Windows usually does file indexing for Windows Search randomly in the background.
