Windows Vista Adobe Flash v.9 Problem

I'm running Firefox and recently I had youtube videos that wouldn't play until I updated Adobe Flash to v.9. At first I couldn't get Adobe to uninstall v. 8; I wound up having to do that manually.

I'm having trouble installing v.9. The installer tells me to quit Firefox, then after doing so it tells me that it has installed v.9 but it doesn't appear that an installer comes up. Aren't I supposed to agree to all the legalese? None of that and no Adobe files found in my app files or data. I've restarted my PC after all these operations.

Videos are sometimes playing again but often without sound or after very long download times.

I'm using Vista home premium, 32 bit.

 

I did and my problem seems to be resolved. Thank you very much for the tip broni!