1984 Data General One laptop
Very cool! Is it still functional?
I don’t know. I haven’t fired it up in over 15 years. It’s just sitting in the carrying case in storage.
I relatively recently got a new laptop, replacing the one that I have had since 2007. It was starting to get angry about updates, and at a certain point, I couldn’t even play youtube videos on it anymore.
It still boots, and I still keep it around as it had a ton of passwords on it, not all of which I thought were relevant enough to transfer over to my new computer.
Under the stairs, I have skeletons of computers dating back to 1992, most of them being late 90’s early 2000’s. I don’t own it, but my first computer, a Tandy 1000 HX from 1985 or so is still in my parent’s basement, though obviously it doesn’t get used much. I did fire it up a few years back to show my nieces what “state of the art” was when I was a kid. Still worked.
I don’t know if it counts, but I do have an abacus that my grandfather had as a kid, so at least 80 years old, as well as my father’s slide rule from high-school.
I still have my Atari 800 with cassette drive. It is utterly unhackable. No virus will ever penetrate it’s security shield. I’ve also got a whole box full of ancient computer magazines. I loved those old games … Zork, etc.
tell me do you have a “hunt the whumpus” cartridge ?
I have a K&E Log Log Duplex Decitrig slide rule from 1947, an IBM PC with 4.77 MHz clock and 64 K of memory from I think 1982, and a Radio Shack MC-10 Color Computer from the early 80’s.
Oldest computer I own? I got it in 1961. It’s 60 years old!
Oldest computer I own? My brain. 
It doesn’t work every day.
I also have an HP-15C. My favorite calculator.
I still have TI-Invaders, I don’t remember the other cartridges. I think there are about a dozen in total.
We are counting stuff in the attic? I may have a Mac that’s even older, but the coolest old computer i have is a NeXT. We used that for years.
That reminds me, I have a few years’ worth of old Dr. Dobb’s Journal magazines from early-mid 90s. I think the only reason I still hang onto them is that several years ago I threw out a whole box of old National Lampoons and I’ve regretted it ever since, and I don’t want to make the same mistake again.
The oldest computer I own doesn’t even compare to the “antiques” some of the posters have. It’s a 2009 HP desktop that works just fine but after spending almost all day late last winter when “working from home” became so in vogue, I tried to load windows 10 and no way no how would it work. After googling ad nauseum and “chatting” with Microsoft’s brain dead “techs” I phoned HP toll free number. They helped me chase down the serial number and thanks to “planned obsolescence” my old computer hardware was simply “not compatible” with windows 10. All the speeds and capacities were plenty large enough but something in the serial number helped detect that I couldn’t download windows 10. It’s still sitting in the basement crawl space. 
Anyway, off to Costco I went for a new desktop!
My oldest computers (buried in the depths of my storage locker) are a TRS-80 Model II and an Apple Mac Plus. The Mac might even still work, but I doubt the TRS-80 does. I also have an original Palm Pilot somewhere.
I used to have a basement full of old computers. I had old PCs including an original IBM 5150, my old Commodore 128 (my C64 bit the dust a long time before that - I wore it out), plus a bunch of old computers that I had come across. I also used to take old computers out of the trash at work and would try to get them running again, which included a bunch of old Vaxes. The fun for me was getting them to work again, and once I got them running I would move on to the next piece of junk. At some point I realized I was filling my basement up with computers that I would never use, so I got rid of all of them. Most went to someone else who collected old computers. Hopefully he put them to good use.
I kept a PDP-11 and a MicroVax III (neither works at this point) as well as a smaller MicroVax 3300. I also kept a little VaxStation 3100 to use as a terminal into the MicroVax 3300.
http://www.vaxhaven.com/MicroVAX_3300
http://home.iae.nl/users/pb0aia/vax/vs3khw.html
None of them have been powered on in years. I doubt that they still work. I may take the MicroVax 3300 and gut it and then turn it into the world’s largest and clunkiest modern PC. I don’t really have enough room for it in my home office though.
As far as working computers go, I have two desktops and two laptops, all of which are only a few years old at the most. The oldest computer in the house is attached to our TV in the living room. It’s an el-cheapo windows 8 PC that is mostly used for streaming (Netflix, Hulu, Youtube, etc).
The older Pentium 4 is probably from about 2005, the newer from from around 2010, my Samsung laptop (which is glacially slow) from maybe 2012. I have a number of old CD-ROM drives in the cupboard and a 3/5" floppy drive, which will probably never be used again.
I threw out a lot of hardware when i moved to Poland from Germany, including things like Japanese power cables (same as US ones, I thought they might come in handy one day) and a number of monitors. It is too easy to be an electronic pack rat. Over the years I threw out a number of old PCs and monitors, in one case I had to dump a very good 19" B&W monitor because Windows 3.0/3.1 had no drivers for it. I used my hardware for as long as I could, but there came a point when the old PCs had too many restrictions, often concerning memory.
One reason for keeping old PCs and old monitors would be to run DOS programs. A 64-bit version of Windows cannot run DOS (I checked) and my very nice monitor cannot run 640 x 480 pixel resolution without changing all the display settings.
Gasp!
That was the first serious/exotic piece of kit I wrote software for. As filthy first-year undergrads, we wrote some stuff in FORTRAN that we straight-ported to C, and then hooked up to a visualizer using Objective C and some convoluted drag-and-drop affair that gave me (very figurative) PTSD when I tried to write something for iOS a few years back.
I would gladly have 10+ yo. computers, but the damn things don’t last that long.
My MacBook pro is from 2015. Maybe it will make it for a decade.
Get Oracle VM Virtual Box (free) and run it as a virtual machine… Takes a little getting used to to be able to install and you need setup disks for the OS you’re going to install but you can then run any version of DOS and/or Windows. I have VMs for DOS 2 (just for interest), 3, 5 & Windows 3.1 (DOS 3.3), XP, 7 & 8 running in VMs. Best thing since sliced bread IMO.
‘Professional’ (or whatever they call it now) versions of Windows 10 allegedly have a VM built-in.
Yeah, Hyper-V. Oracle Virtual Box is much more intuitive and much less fiddly (IMHO). I prefer Virtual Box so of course we have standardized on Hyper-V at work. Blech.
At home I use Virtual Box to run Windows XP for some old software that just won’t run on anything later.
DOSBox is another option for old DOS programs.