Flash Not Staying Installed - Need To Reinstall Multiple Times Daily?

System: Dell Inspiron laptop,
Studio 16 XPS
Windows 7 Home Premium w/Service Pack 1 (64 bit)
Intel Core Duo 2.8 Ghz, 4 GB RAM.

The problem is that Flash will not stay installed. Another problem (related?) is that I *cannot* install Itunes on this computer, it will error out each time, and Apple is notorious for telling me it is a Windows problem, nothing they can do, so I found a way around the "long pole in the tent" requirement of Itunes to Sync iPad/iPod, and this really isn't even a "problem" anymore as much as an annoyance. Other utilities, Avast virus protection, Malware Bytes, Spybot Search/Destroy with immunization, and always running Iolo System Mechanic.

All software and operating system is up to date with current patches and updates. A program I use regularly that may be suspect but also seems so innocuous as to have no bearing on it is a keyboard macro program, Keyboard Express v4. For example with this program, I can define some hot keys like ALT-CTRL-T which will insert some text I define to the program into wherever the cursor is at on the current web page or Word document. Always text, no graphics or funkiness here.

I usually use Firefox (v11.0) as my browser but interestingly enough, I discover that Flash has also disappeared when I go to IE (v9), and it appears there is a different Flash for IE than there is for Firefox, depending on which browser is used to download (multiple times daily) the Flash installer. An interesting aspect is that after I re-install Flash, IE and/or Firefox, then later on go to Outlook and click a link in an email, Outlook gives me an error message about not being able to open the link. But if I reboot, Outlook is now fine to click on and open that same link, although Flash has again gone away.