We got about the same here.
Companies dump their old systems and people on welfare can get them "in loan" without any costs.
Downside is that those systems barely can run XP
I don't know how many systems you are talking about, so it can take "some" time to check but here are a few tips/thing to check/keep in mind if you are looking to upgrade the OS on them.
Windows 7 can run on systems that don't support the SSE-2 (and higher) instruction set.
Windows 8 and up need a system that can handle SSE-2 instructions.
You can ofcourse find out and lookup the specifications of the cpu's in the systems, but there is a easier way.
http://www.ache.nl/cgi-bin/download.pl?file=everesthome220.exeThat is a old and free tool that you can use to get information about a system.
Since they are old(er) systems, updating the OS to Windows 7 seems the way to go.
The cpu (=main processor) is not (likely) gonna be a problem.
Even a 15-20 year old one is capable of handling Windows 7.
The problem is mainly to get it all software running at a acceptable speed.
Although Windows 7 will run with as little as 1Gb ram, I advise to use at least 2Gb in a system.
Often on those old systems 2Gb is the maximum that the motherboard (chipset) can handle.
If it supports more and you can get your hands on it...
Go for it !
1Gb and 2Gb memory stick (DDR SDram which almost all those systems are using) can be bought for as low as 2 USD (new price) per stick.
Second thing to look at is the video/graphics.
If a system has onboard graphics, put a graphics card in the system and disable the onboard graphics.
Onboard graphics are using part of the normal memory and that is slowing down things a lot.
Best is to use AGP cards as they are faster than PCI cards.
It is easy to see if a system supports AGP.
Everest (the tool I mentioned earlier) can tell you.
Or you can look in the bios or open the system and physically look
To see how they look (desktop card slots) >
http://media.techtarget.com/whatismedia/images/hardware-chart-large.pngThe more memory a graphic card has the better/faster it will work.
A card with 512Mb memory is about 40 USD (new price)
I would say :
1]
ask local computer stores if they have some "old stuff" laying around (memory & video cards). Perhaps they are willing to donate them.
2]
Put up a add at local supermarkets (or where it is possible) and ask if people have something laying around that they don't use.
3]
Perhaps it is possible to get a free add in a local newspaper or get some attention for it on a local radio station