Less a solution than a reaction to having created a separate thread with my experiences with this topic...........adding that posting HERE since it isn't getting any traction on its own.
searching on this topic, I see there are a boatload of folks in similar situations as I am with slightly varying symptoms. In my case, I have a Dell Inspiron 17R SE that was originally going to ship with Win7 on it. BUT, I went past Microsoft's (apparently) "blackmail" deadline at which point Dell was evidently not allowed to ship anything Win7. SOOOOO my laptop showed up with Win8. I don't want to rip Win8 completely out, as the next upgrade path might depend on it being there (a guess) plus many of the updates from Hell, er, Dell :-) seem to assume Win8 being present. My best guess was to make the system dual-boot but I don't think I need to go too far into what a pain in the a** that turned out to be. Plan B - the laptop is designed to have a second hard drive installed, so why not have one with Win8 and put Win7 on the other - thus keeping the different boot systems separate. Well, so long as the Win8 HDD was physically IN the machine, Win7 absolutely would NOT install. I played the little games with the BIOS with legacy-this and UEFI that and finally came to the conclusion that the next best step to try was to simply remove the Win8 drive and set the laptop to boot from the optical drive with the install disk in. Ya know, that worked - Win7 installed on the new HDD slicker (and darned fast, too) that I imagined. OK, one obstacle over with. Power the system off and put the Win8 HDD back in. System complained a bit at first but eventually I got to a point where I could select which HDD to boot from. Cool. Here's where the fun (fun? who the heck am I kidding with THAT???? ) begins. When booted into Win8, the system sees the new HDD just fine. When I boot into Win7, I cannot find the Win8 drive AT ALL. That, as you might guess, is where all my other stuff is located...data files, some apps that I installed like Adobe CS6 and Microsoft Office, etc. Looking around the web at various forums, there is also the suggestion that such a Win7 install may also find itself with driver issues. I never thought of that and I probably should have; I may have subconsciously assumed that there may have been some backwards compatibility in that department. Well, so here I am to see who may have any brilliant ideas for me and/or good questions to ask that might lead to brilliant ideas and possibly solutions. If it helps any, the Win8 that came installed on the machine is Win8 Home. The Win7 that I put on the second drive is Win7 Pro AND I have a Win8 Pro upgrade disk which I have so far not attempted to use. I mention THAT because I seem to be seeing some comments that Win8 Pro *might* have some features that would make this problem easier to sort out.
So the flag is up the proverbial pole, anybody want to salute? :-)