All computers [of the same model] were created equal, but time has shown that they do not remain equal even if they are never upgraded. Every computer develops its own quirks with time which range from minor annoyance to irritation. Software also has a hand in the kinds of personality traits that arise in a computer.
If there are traits that have come and gone, they can also shape the quirks that have since arisen. Though much of what I call quirks and traits are in fact technical or hardware issues that have some kind of fix, it's not so interfering as to demand a permanent solution.
I myself have had a few computers with interesting personalities.
My 2003 VAIO Laptop developed a tendency to have IE crash the first three times I tried to open it, only working after I opened it for the fourth time. Firefox refused to uninstall, update, or just plain work.
The CD drive sometimes did nothing but "hiccup" while it spun the CD...without reading it.
As for my desktop, I would best describe it as a healthy old man who has occasional bouts of senility and a poor ability to get rid of excess heat.
Regarding the latter, the issue was prominent when I still had a graphics card that usually ran at around 70-degrees Celsius at system idle. With the help of a removed case cover and a 15" table fan, it ran around 45-50-degrees Celsius at system idle speed. Essentially, if I didn't have the fan blowing on that thing while playing a game involving heavy 3D graphics, the computer would shut itself off without warning roughly 30 minutes later. Temperature safety devices at work, I suppose.
No surprise, I'd usually reboot the computer to find that hal.dll was corrupted and preventing Windows from loading. I had a spare copy of it around as well as a Linux Mint disk, so it was no big issue aside from having to re-enter the Vista product key. Finally broke the camel's back, I think, when I dared to see if my new power supply and its huge intake fan would help the heat issue. It wasn't hal.dll that time around--it was a whole list of essential services that didn't have a whole lot to do with hardware. No surprise at any of this considering my desktop is about 8 years old, and a "Frankenstein" to boot.
As for senility, it has rare (maybe once every several months) moments where it'll hang and BSOD on me. Recently, some spat between Windows Update and my computer that happened at 3:00 AM (read: I was knocked out) caused my user profile to become corrupt. Luckily, there was a fix for it, albeit with no ultimate reason given behind the corruption. I lost my desktop wallpaper, but that was it.
That said, I'd like to hear what others have to share about their computer's personality.