Odd issue, expecially since the Health Warning is showing. Can’t suggest anything specific unfortunately. Just things you might already have tried: Reboot, switching between runtime 0.7/0.8, trying another display driver, restoring a Windows system restore point from before the issue started to occur.
BTW: A Geforce 760 may be a bit too slow for many newer games with the latest vorpX version. Oculus recommends a GTX 970 class GPU for the Rift. Has nothing to do with the issue, just thought it was worth mentioning.