On January 14, 2020, Microsoft is retiring Windows Server 2008 and Windows 7. When Microsoft retires an operating system, it ceases to maintain it, provide critical patches or provide support for system issues. You might be running one or both of these operating systems.
What does “End of Support” mean?
If you continue to use Windows versions after support has ended, your PC or server will still work, but may become more vulnerable to security risks and viruses. Microsoft will no longer provide the following support for your business.
No Technical Support
No Software Updates
No Security Updates
Source: Upgrade Windows | TechCentral
The last time this happened, when Microsoft ended support for Windows XP, a vicious strain if ransomware called Wannacry infected computers all over the world, including the National Health Service on the UK. If you do not upgrade you are at risk. If you do suffer a data attack you will have no defense when the HIPAA police come calling.
Rather than buying all new machines you may want to consider renting your hardware infrastructure as a service. This is called HaaS (hardware as a service).