...Well...I do have quite a bit of experience with computer building, but only silent ones because despite being functionally unable to use sound, noise really hurts! I prefer my computer to make an imperceptible level of sound. If you are also interested in a very quiet or completely silent computer, then I would be more than happy to provide guidance on the components to make one yourself! (I understand you've indicated interest may be the issue, but throwing it out there nonetheless.) If you wanted a silent laptop, I can offer a list of suggestions. If not, here's some people in the UK that I know can help you out if you wanted a silent-running model as off-the-shelf as it gets in desktop-land: [LINK]
I do think swapping out your hard drive for a SSD could improve all of the problems you're experiencing, so if you want to try, it's pretty easy to swap even in the most ultra-portable (a.k.a.: ultra-cramped) laptops. Can you let me know what form of PC you have now so I can determine what kind of SSD size/mounting would work for you? It sounds like you may have a Commercial-Off-the-Shelf (COTS) model: if so, please let me know the model number and I'd be able to determine everything I need from that to help.
Here's something that may feed your anxiety, but that I feel compelled to state in relation to your perception of "used" PC's: if you didn't build it yourself with virgin components, any COTS model unit or custom-built PC is going to be previously "used" in terms of someone else having full access to it to do whatever they wanted...no one sells PC's that doesn't at least do a boot check, and most of them have a diagnostic check they do on the OS shipped too before setting it to "factory default" settings so the computer looks like it is booting up for "first use" when you first turn it on. There is no telling what has been done to the PC before you receive it, and techs are usually encouraged to engage in "standard use" of a PC for a while during and after diagnostics are run to break it in.
Unless you know how to do a complete software and hardware forensic evaluation yourself...every big name PC manufacturer in the past two decades have at some point got themselves into hot water for their role in corporate espionage and/or security breach incidents for hardware installed on COTS models (i.e.: DELL, Lenovo, Toshiba, HP, Sony, Samsung, Asus, Alphabet), so there's going to be that. That said, for SSD and other components, there is a limited life in terms of cycling as well: so with "new" computers you won't have to be concerned with much of that being used up, though.
I do think swapping out your hard drive for a SSD could improve all of the problems you're experiencing, so if you want to try, it's pretty easy to swap even in the most ultra-portable (a.k.a.: ultra-cramped) laptops. Can you let me know what form of PC you have now so I can determine what kind of SSD size/mounting would work for you? It sounds like you may have a Commercial-Off-the-Shelf (COTS) model: if so, please let me know the model number and I'd be able to determine everything I need from that to help.
Here's something that may feed your anxiety, but that I feel compelled to state in relation to your perception of "used" PC's: if you didn't build it yourself with virgin components, any COTS model unit or custom-built PC is going to be previously "used" in terms of someone else having full access to it to do whatever they wanted...no one sells PC's that doesn't at least do a boot check, and most of them have a diagnostic check they do on the OS shipped too before setting it to "factory default" settings so the computer looks like it is booting up for "first use" when you first turn it on. There is no telling what has been done to the PC before you receive it, and techs are usually encouraged to engage in "standard use" of a PC for a while during and after diagnostics are run to break it in.
Unless you know how to do a complete software and hardware forensic evaluation yourself...every big name PC manufacturer in the past two decades have at some point got themselves into hot water for their role in corporate espionage and/or security breach incidents for hardware installed on COTS models (i.e.: DELL, Lenovo, Toshiba, HP, Sony, Samsung, Asus, Alphabet), so there's going to be that. That said, for SSD and other components, there is a limited life in terms of cycling as well: so with "new" computers you won't have to be concerned with much of that being used up, though.