I am happy to report that I was able to install the Samsung SSD 850 EVO (500 Gb) on my Dell Optiplex 780. It's like a new computer! The boot time is several orders of magnitude quicker than before, and documents load more or less instantly, even huge PDFs.
I ran into a number of trial and tribulations on the way. I will mention some of them in the hope that it might help others.
1. After I installed the SSD and Windows 7 Professional, I installed the Samsung Magician software, which told me that AHCI was not enabled. No problem, I thought. I'll just re-boot, press F-12 during the boot sequence, and change the drive setting.
In the boot menu of the Optiplex 780, there are four choices:
Raid Autodetect / AHCI
Raid Autodetect / ATA
Raid on
Legacy
"Raid on" was selected. I changed the selection to "Raid Autodetect / AHCI" by clicking on the radio button, applied the change, and exited. But upon booting, the computer would hang. Some research on the Internet suggested that the choice of AHCI has to be made BEFORE the operating system is installed.
Lesson 1: Change to AHCI before installing the operating system on the SSD.
2. To reinstall the operating system, I figured it would be a good idea to reformat the SSD. The closest that the Samsung Magician program comes to this is a "secure format" which erases everything on the disk. So I run the "secure format" which has to be run from a bootable disk (that I had to create), but the program then tells me that there is a "security freeze" on the disk. To unfreeze the disk, I am instructed to remove the cover to the computer and, while the system is still on, unplug the power cable from the SSD for few secondes and then re-attach. Then type in SEGUIO.EXE to run a program from the CD. Well, that is an recognized command. Remembering my DOS commands, I change directories and list the files and eventually realize that what looks like SEGUIO.EXE on the screen is actually SEGUI0.EXE. In other words, the letter O was really a zero. But it was indistinguishable on the screen under the program because no slash showed up on the zero (it was distinguishable, however, under DOS).
WHAT MORON AT SAMSUNG THOUGHT IT WOULD BE A GOOD IDEA TO ADD A ZERO AT THE END OF THE PROGRAM NAME??? Why add a number at all? If one must add a number, why not a distinguishable number. If version control must be reflected in the file name (and you're so neurotic a techie that you must start with zero instead of 1 like normal people), why not SEGUI_A.EXE for the first version? /Rant over.
Lesson 2: If Samsung tells you to run a program named SEGUIO.EXE, understand that what looks like an O is actaully a zero.
3. I re-installed Windows after selecting "Raid Autodetect / AHCI." No problem with the installation. But big problem with Windows update. Many "important" updates failed, even after repeated attempts with manual updating. Shockingly, Microsoft's Fix-It program didn't work. /Irony over.
Lesson 3: Microsoft is more stubborn than you are, and it has a lot more patience than you. Go with the flow.
4. I finally give up on Windows 7 and decide to install Windows 10. I thought, why not download the OS and have it handy on disk. I download both the 32-bit and 64-bit versions in one file, but the file was too big to fit on a DVD.
So I download the 32-bit version, burn a DVD, and install the program. It asks for the Product Key. No problem. I've got in on the sticker on my machine. I enter the key, and Microsoft tells me that, "Hey, that looks an OEM version. We won't install the program. Speak to your vendor."
So I elect the option to "Install on this PC." That works, and I end up with Windows 10 on my PC.
Lesson 4: The simplest solution is usually the best solution. Occam's Razor and all that.
5. I re-install my programs and go to transfer the files and settings, which I dutifully backed up using Windows Easy Transfer. Hmm, it turns out that Windows Easy Transfer is not part of Windows 10, and a different program must be used, a program does not run on Windows 7.
The new method under Windows 10 requires hooking up one computer to another computer, not transferring files to an external USB drive. I put the old hard drive in my son's computer as the C: drive, but it won't boot.
So I make it an additional drive and hook up a cross-over cable to connect my son's computer with the computer with the new SSD. I read on the Internet that the cable Laplink is offering for sale is essentially a cross-over cable. No go.
I then try the Belkin USB Easy Transfer cable for Windows 7 that I bought for use with Windows Easy Transfer in an earlier era. It looks just like the USB transfer cable that Laplink is offering to sell for use with the "free" version of the Laplink program that Microsoft offers instead of Easy Transfer. No joy there either.
I finally decide to transfer the Outlook .PST file to the new SSD via USB, enter the settings for Outlook manually (which I dutifully noted at the outset), tranfer the Favorites that were exported from IE Explorer, and make any other necesary adjustments to the settings manually. I transfer selected files to the new SSD, and I'm in business!
Lesson 5: Don't think that Microsoft is going to make it easy to transfer files and settings. Research the method ahead of time. Or break down and buy the damned cable that Laplink is offering to sell you so you can use the "free" version of its program. Just don't assume that it will work with the next iteration of Windows when you have to transfer files and settings again.
Once again, thanks to all who responded. You gave me the courage to set off on this trail-blazing (for me) journey, and any arrows in my back are actually trophies evidencing knowledge gained in the effort.