If you want to know what you have go control panel > system and you will get a screen like this one.[Image was removed]
Check the arrows for where you can get the specs.
Now assuming that its time for an upgrade, and you want to buy new hardware for your POS software, here is what I would recommend as your minimum specifications.
As buying a computer for business is not the same as buying a computer for home. At home, if my computer goes down tonight, and I have to wait until tomorrow for an engineer to fix it, is not serious. If a server goes down in the shop for a few hours, it can bring the shop to a halt. The other problem is that you are paying for time. Say, for example, a computer takes 3 minutes longer a day to do its work over four years that 3 minutes would cost you about
360 days x 3 minutes x $26 hour / 60 minutes x 4 years = $1,872.
Of course, modern computers are saving more than 3 minutes a day.
Now the operating system, I recommend is Windows 10. Not only does it run the fastest and latest SQL 2016. Its is also that Windows 7 is already out of mainstream support and has only about two years left of support which is not long enough as most of us buy a computer for 3 to 5 years. Windows 8, I do not recommend at all as do few others, which leave us with Windows 10. Plus of course, why buy something new, to have something old like Windows 7.
This does present a problem in that Windows 10 uses a lot more RAM than previous versions of Windows. I have noticed on a 4GB RAM computer about half the RAM is just being used by windows 10. However, it seems that extra RAM is required even by people now on Windows 7 as some of the updates have caused their RAM requirements to go up too, that is partly why the old computers are slowing down. So I would recommend as the price has dropped that you insist on RAM of no less than 16GB, and I would strongly recommend the new DDR4 RAM as its faster.
For the hard drives, it depends what important to you if speed is all powerful, then get the SSD, which will give you less space, then an HDD but faster speeds, if, however, you need lots of storage, then select the bigger mechanical HDD (Hard Disk Drive). On both systems, our software runs well.
As far as CPUs, I would not recommend anything under 3.30 GHz. Anything less is just too slow today.
Video card generally in point of sale is not so important as the graphics are rarely that demanding so I would not be so concerned about that.
Monitor size is a hard question, Often it depends on what can fit in a spot if it's too big, and it does not fit, then the monitor is useless. Another point I find is that people have very different preferences. It really worthwhile checking out a few sizes to find the one suitable for yourself. Now if you have older people that will be using the monitor, particularly if they are a bit of a distance from the monitor remember they have to read the screen too so maybe get something a bit bigger. Then the other problem you have to balance is that if it's too big, extended use can hurt people's eyes.
I hope this helps; any questions let me know.