Hi Steeboo:
The minimum system requirements for Win 7 are posted at https://support.microsoft.com/en-ca/help/10737/windows-7-system-requirements and include:
- a 1 GHz or faster processor
- 1 GB (32-bit OS) or 2 GB (64-bit OS) of RAM,
- 16 GB (32-bit) or 20 GB (64-bit) available disk space
- a DirectX 9 graphics device with WDDM 1.0 or higher driver.
Run the Windows 7 Upgrade Advisor (https://www.microsoft.com/en-us/download/details.aspx?id=20) on her Vista machine to see if the existing hardware and peripherals are compatible with Win 7.
Most AMD Sempron 3400+ CPUs run @1.8 GHz so I assume the current CPU and 1.5 GB of RAM will meet minimum requirements for a 32-bit machine, although I'm not sure how well the system would perform with those specs.
32-bit Vista Home Premium SP2 * Firefox ESR v52.2.1 * NS Premium v22.10.0.85