Just follow jdow's excellent advice. It should fix your problem.
I only needed to follow steps 5 & 6 (due to previous installation) on my Window 7 PC with a more recent SDR# release to get
my NooElec (RTLSDR device) dongle working again with recent SDR# release.
These days I usually only use the NooElec for DAB+ reception or for the occasional investigation of freqs that the HF+ doesn't cover.