I am running across large numbers of XP, Vista and Window 7 users who are all complaining over the root certificate woes. Windows 10 will still upgrade Windows 7. XP and Vista users will be better off with a new rig. An alternative is to run Linux which has easy system requirements.
Widespread complaints of websites showing certificates are not valid. They actually are, the problem is the system certificates to check with are obsolete. Linux is free.
Back when XP was new I was using 2048MB RAM which was all that Windows could handle. Then on 2005 when XP 64-bit was offered I grabbed it immediately and upgraded my machine. I have used 64-bit Windows ever since.
The low cost AMD Athlon 3000G supports Windows 10 and Windows 11 fine. A low cost B550 motherboard is all that is needed, The RAM has come way down in price too and 4x4GB is now under $60, A low cost $59.99 chassis is fine but get a good quality PSU to prevent problems. Procrastination will make things worse.
Many websites are also showing certificate errors. This is because the webserver is not maintained properly. A lot of work is needed to maintain websites but advertising revenue has been poor.