I don't have sound; unable

Question

i don't have sound; unable to view videos; i have tried defrag; clean up; the message i get is; "file can't be played-system does not have required compressor-decompressor (codec) installed." also i have a "document viewer" popup with the message: the feature you are trying to use is on a cd rom or other removable disc not available, unsert document viewer....would re-installing my photoshop elements help any?