How Can I Fix Video & Audio Problems in Premiere Pro CC (Unlinked Media & No Audio)

Late last year, after a few months of having used Premiere Pro CC, I started getting the 'Unlinked Media' error on video clips with audio without having modified these in any way since I last had the project open. Attempting to relink or replace footage would bring back the video, but I would be informed that it did not contain the associated audio now, so I would lose all the audio from those video files in whatever project I was working on completely, if I weren't fortunate enough to have exported it beforehand. After this these videos would never appear with any audio if I imported them into a project, forcing me to use separate video and audio files for this clip. Over time the frequency of this error has only increased, to the point where now it is having an extreme impact on my productivity using the software.

I've already checked around for solutions, and tried a few. One suggested cleaning out my Cache files, which didn't seem to help, while another linked a program called 'MPEG Streamclip' to essentially re-encode the videos so they'd work, which worked for the first day I used it before the same error persisted once again. At this point, it appears that every single video clip with audio I put into Premiere Pro CC comes up as having no associated audio, even ones exported from the software itself, making editing with the software increasingly difficult and time consuming for me in a way I feel is unfair given the monthly subscription I pay to keep it.

If there are any solutions for this problem I haven't yet tried I would be extremely grateful to hear them.