I don't use my computer for any type of "work". Basically, I just use it for email, news, shopping, paying bills, watching movies, playing games (hidden object/match3/solitaire/adventure/time management games) I do have the need for some type of WORD program for typing letters, recipes etc.
You could try Linux on the old PC, It is not as hard as you think and with what you use the PC for you would hardly notice the switch.
Think about it and if interested we can help you.
The other benefit of switching to Linux is you wont need a new PC.
I am going to show my "ignorance" here, what is Linux?
The Unix operating system was conceived in 1969 and in the late eighties work began on a variation of this OS called Linux.
It mostly free and 'open source' so there are many people writing there own varients all with silly geeky names, about 250 distrobutions are available.
The Mac OS is also based on Unix as well and most people are strangely happy to run it on their smart phone or tablet (Arm/Android)but not on their PC, not much choice when you buy a New PC though! It comes with Windows predominately, without a choice.
You can run both on the same machine as I do and benefit from both at no extra cost, one of the distro's I use called AV Linux comes with very good free video and Audio editing software amongst other programs and apart from Publisher files the free WP is ok for most uses in all the Linux distro's I've used.
The average full install of a Linux OS with loads of free software is usually around a third of the size of a typical Windows install without a load of useful bundled sofware.
Installation varies greatly from distro to distro and precautions must be taken before attempting to do so, not usually for a novice.
I found a real appreciation for the OS and although I've a few headaches along the way I couldn't live without it now, fewer updates and often no need to reboot after, a little faster, less memory hungry and a little more secure.
OK I do a scan now and then with 'rkhunter' and or 'chkrootkit' but over a year running with no AV program installed.
I like choice and With Windows I don't have one I work for them, I do all the virus scans, constant updates etc... and I'm the one who pays out for the computer repair shop to get rid of the malware on it or learn from forums like this to be savvy, surf carefully and try and be careful what you click on, all helps!
Research the options and make choice, I did! I'm in the construction industry BTW so no Steven Hawkings by any means.
It's kind of like having two girl friends, ones always late, smacks you around the head with a vase and gives you loads of grief, the other uses a pillow instead and does what she is told most of the time. LOL I'm cath fire for that!