I just responded to the "Update available - click here to install" on my desktop. After the install Norton informs me that it found TROJAN.ADH.2 in adobeflashplayerpluginupdatesetup.exe and quarantined it. I also am at a loss - not very knowledgeable about these things. But a Trojan doesn't sound good! Norton also tells me that adobereaderupdatesetup.exe has "Suspicious.Cloud.9" - whatever the heck THAT means.
Now my Norton tells me it has found this same Trojan.ADH.2 in firefoxupdatesetup.exe AND microsoftsilverlightupdatesetup.exe. And the only place I seem to be able to appeal for help is to fellow users like yourself. I've never used these community postings before and am so lost. And I just don't have the time to sit around and wait for someone to pass by, take and interest in my plight and care enough to reply. Not that I would understand the reply & know what to do with it if it did come.
Good luck to you!