I checked the site Andie advised, http://www.adobe.com/products/flashplayer/tech-specs.html, & saw that the compatibility issues are the most frequent specs for adobe not getting installed.
However, I also checked my task manager while installing on my own system, it becomes that there are times when there are 2 activex flash getting updated, & that the flash updates is on, which is countering the flash installation, which makes an error.
If this is the case, please end the 2nd running update, & it will work.
Hope this helps.
Cheers!