Opening Zip File for 11.2 help?

So I stupidly updated my Flash to 11.5 again. It seems that a lot of people deal with the choppy sound and such. Normally I can find a fix but this time it's just not happening. I am not a tech savvy person, I found a zip file for the old 11.2 which I can download and then disable 11.5 in Chrome Plugins but the question is HOW do I do this? I don't know where to open the Zip or where to put it so it works. Running Windows XP in Google Chrome. Thanks for any help!