NetfxRepairTool said
Reregister Windows Installer service
Unregisters and re-registers the Windows Installer service using MsiExec.exe.
Restart Windows Installer service
Stops and restarts the Windows Installer service. Applicable regardless of the diagnosis results.
I did that and tried dotnet4.5 again and it failed again.
Log file says
OS Version = 6.1.7601, SP = 1.0, Platform 2, Service Pack 1
OS Description = Windows 7 - x86 Ultimate Edition Service Pack 1
MSI = 5.0.7601.24535
Windows version = x86_windowsfoundation_31bf3856ad364e35_6.1.7601.17514_none_0541445eeedbd616.manifest
Windows servicing = 6.1.7601.24544
CommandLine = D:\781f0fa6e03d49c34d\\Setup.exe /x86 /x64 /web
TimeZone = GMT Daylight Time
Initial LCID = 2057
Using Simultaneous Download and Install mechanism
Operation: Installing
Package Name = Microsoft .NET Framework 4.5 Setup
Package Version = 4.5.50709
User Experience Data Collection Policy: Disabled
Number of applicable items: 8
Exe (D:\781f0fa6e03d49c34d\SetupUtility.exe) succeeded.
Exe Log File: dd_SetupUtility.txt
ServiceControl operation succeeded!
Exe (D:\781f0fa6e03d49c34d\SetupUtility.exe) succeeded.
Exe Log File: dd_SetupUtility.txt
MSI (D:\781f0fa6e03d49c34d\netfx_Full_x86.msi) Installation failed. Msi Log: Microsoft .NET Framework 4.5 Setup_20200709_184125754-MSI_netfx_Full_x86.msi.txt
Final Result: Installation failed with error code: (0x80070643), "Fatal error during installation. " (Elapsed time: 0 00:00:24).
NetfxRepairTool then suggests repairing dotnet 4.8 (The install of 4.8 failed as mentioned in my originqal post so I am unclear why there is anything to repair!!)
This reported repaired OK try reinstalling
but of course that doesn't work. Tthe error is
"Details
Same or higher version of .NET Framework 4.5 has already been installed on this computer."
Little point in sending the log so I thought I'd go back and have another go at installing the windows updates
Windows update says updates have never been checked or installed
Eventually it find one (KB2319138)
That installed OK but it says there are more updates
On searching says there are no important updates
So it looks like its fixed and was mostly to do with the failed dotnet 4.8 install/
I will reboot and search again but thanks for your help