You should be able to SEE read-only files, I've never seen it otherwise. So I don't understand the problem. Two things that might be relevant are (1) many flash drives have a write protect switch, and (2) is it possible the flash drive is somehow damaged or worn out? They can wear out after a whole lot of use.
Can you copy the files to your hard drive? If so, you should be able to remove the read-only setting by right-clicking and clicking Properties. However it sounds like your problem isn't really a read only setting or you should be able to at least see them. One final thought - you should always keep more than one copy of anything you don't want to lose because there are all kinds of undesirable things that can happen.
Good luck.