Just thinking that I should order some supplies to help with computer maintenance, and I am wondering what to put on the list:

Current (relevant) desktop PC specs:
CPU: Intel i5-4670 (non-K so no overclocking); rated at 3.4GHz, but running at 1.4GHz.
GPU: Integrated HD 4600 series I believe
RAM: 16 GB (has room to add another 2 sticks IIRC)
2 SATA drives (SSD and spinning rust)
Motherboard: Asrock H87 Pro4
OS: Debian GNU/Linux (no Windows license on this machine)

Thermal info:
* Idles at 50 C
* Fan is supposed to go on at 80 C, but doesn't
* Throttles at 100 C to around 250MHz (unusably slow unless I switch to the terminal)
* If running at 100 C for too long, will shut down
* Case fans at least seem to be working

Anyway, currently I am looking at getting the following:
* Some tool to remove dust from the computer (I would be *really* surprised if there were no dust)
* A CPU cooler
* Something to help with cable management (any advice?)
* A screwdriver that would work for installing PCIe SSDs (not for this computer) (anyone know what type I need?)
* An HDMI switch or splitter (so I can switch my monitor to another HDMI device without having to disconnect cables)

So, any advice here?
(Note: I am not currently looking at upgrading anything other than the cooler at the moment.)

Edit: Why the low rating?

Get an air duster (compressed air can; something like this https://www.amazon.co.uk/Star-Duster-Compressed-Flammable-400ml/dp/B000MQ7DZC) and an anti-static brush.

Resist the temptation to use a vacuum cleaner on the insides of your PC - it won't end well!

Not to mention that vacuum cleaner is highly ineffective for this (I was doing it in the past, luckily I didn't kill anything). Aged dust will just be immune to it and stay in place. You really need to blow and not suck in these cases so I second the compressed air recommendation.

I just did it a week ago after neglecting it for a few years and my GPU fans got a lot quieter when under full load, so it definitely helps.

A Datavac for dusting computer equipment is better than canned air.

https://metrovac.com/products/datavac-electric-duster?variant=18877237067849

Secondly, you might want to consider reapplying thermal paste to your CPU and discrete GPU if you have one. This is a very easy process and there are many videos on Youtube showing how to do it.

Thirdly, you might want to take a look at cable management and make sure all wires/cables are tucked out of the way and you have good airflow inside the PC case.

Finally, consider adding more or better intake and exhaust fans.

Your CPU obviously has overheating issues, so these should be your top priorities. It might actually have an effect notable enough that anything else would be trivial in comparison, so I would not get anything else until the CPU cooling system is fixed.

By the way, do not forget to buy some thermal paste. You will need to put some between the CPU and its new cooling system.

Your processor's temperatures definitely shouldn't be that high, as it is a desktop (more reasonable would be ~45°C idle and max 75-80°C under load). Are you, in fact, using a CPU cooler (you haven't listed any under your current specifications)? If so, it might help to reapply the thermal paste between the cooler and CPU. If not, it is likely a good idea to get one.

Oooo - I've not seen one of those before. Do you have one and are they worth the money? It's a big price hike over a can of air, which might not be perfect, but it does clear a good portion of the dust.

You will need some thermal paste

https://www.amazon.ca/ARCTIC-MX-4-2019-Performance-Durability/dp/B07L9BDY3T/ref=sr_1_7?dchild=1&keywords=thermal+paste&qid=1611847988&sr=8-7

And a compressed air can to blow the fan of the heatsink, Easy work tbh and should work with you

This is like a novel adventure which you follow over the years... a bit like GoT you know.... Will the cpu finally be relieved of its heating adventure or will it break down before hand, will the new pc arrive before this one works for only one last time.... Exciting adventures !!! i'm curious to see how it will turn out.... if we would learn the truth that is... at least i would never admit to blowing up my own machine ( guess why i changed my r5 2600 .... ( bad ticket to begin with, don't get me wrong )

I'm really surprised you haven't burned out your CPU by running without a functioning fan. That should absolutely be your immediate priority. I've used this one in a few simple builds I've done for friends (it also includes pre-applied thermal compound, so no need to buy a tube):

https://www.amazon.com/Cooler-Master-i30-CPU-RH-I30-26FK-R1/dp/B07QQXCVVR/ref=sr_1_1?crid=2I9DVPP9CPU0&dchild=1&keywords=lga+1155+cpu+cooler&qid=1611848682&sprefix=lga+1155+%2Caps%2C212&sr=8-1

I have no experience with HDMI splitters, but I know you can get good 2 or 3 port models for under $20. Unless you have very specialized requirements or are doing professional video editing you probably don't need the expensive $80 - $90+ models.

For the other items: use a can of compressed air to blow out the dust, a pack of zip ties for cable management, and a thin Philips head screwdriver for the SSD. No need for anything exotic and expensive: the cheap stuff work fine.

Some coolers have paste pre applied, others don't. Anyway, any thermal paste is ok, you don't need anything fancy.

A can of compressed air works the best to remove dust but do it outside or dust will get everywhere (well,blowing means that right?). I also use a brush to help loosen the dust, something like a old toothbrush or a painters brush do.

The cooler depends on your case but if it's a ATX or micro-ATX case, pretty much any will do. Keep in mind you need one with actually fits 1156/1155/1151/1150 Intel sockets (almost all fit but make sure). Something like the stock cooler or the Cooler Master i117 is more than enough to keep things cool enough. Dont forget a couple of grams of thermals paste if the cooler don't have it pre-applied.

Cable management is usually done with zip ties or velcro ties. I usually use black wire, the wire that comes tie package bags.

PCI-e SSD's are usually held by a PH2 Philips screw on the case, M.2 SSD's almost universaly use PH1 Philips driver.
A simple screw driver kit with interchangeable bits is not expensive and got you covered in most situations.


Edit: most coolers ship with a bit of thermal paste in a bag. I actually never used a cooler that didn't shipped with thermal paste either pre-applied or in a small container.

As other said, cans of compressed air or a portable air compressor will do wonders for dusting. Just don't go wild on the pressure, as not that much is needed usually. Having some isopropyl alcohol (IPA99) around also helps with more consistent dirt, clearing out old thermal paste and repasting etc. Some vacuums have a reverse/blower function which is mostly fine for computer "dusting", but I don't recommend using it either otherwise.

Modern CPUs will not burn out, people, rather thermal throttle to hell. I'm not saying it's good for a CPU to be run at 90+ C, but it will certainly not fry itself if your fan dies. Make it go on at 40 or at most 50 C if possible (when fixed, of course) - can be with a lower RPM at those temps, but even a slight airflow over a radiator drastically increases coiling efficiency over exclusively passive cooling.

Beware of thermal paste that acts like superglue.