Hope you don't mind me chiming in, Aura. I understand it's an issue affecting 64 bit Windows 8.1 and 10. The 64bit versions require the CPU to have support for CMPXCHG16B, PREFETCHW and LAHF/SAHF instructions. The Pentium E5300 does support CMPXCHG16B and LAHF/SAHF at the CPU level, according to CPU World. I'm not totally sure on PREFETCHW. The newer Core iX series do support it. Discussion here on superuser.com.
There is a utility from Microsoft Sysinternals: coreinfo that checks your CPU's capabilities. Run it and check that these instructions are supported by the CPU. If not then I think you are out of luck.
A possibility I have read of while researching this is that the BIOS could be disabling some of the CPU features. You could try
- Updating the BIOS, if a new version is available
- If no BIOS update available you could try resetting the BIOS to default values and/or...
- See if the BIOS contains any reference to enabling or disabling CompareExchange128 or CMPXCHG16B (I've never seen it in a BIOS, but it's possible). NX/XD Bit also need to be enabled for Windows 10. I understand LAHF/SAHF are part of Intel's VT-x feature so enable this also.
And if all else fails...
- Use a 32 bit version instead (it's not possible to in place upgrade from a 64bit W7 to 32bit W10). You'd probably have to start from a clean 32bit install of Windows 7.
An issue some running Windows 8 x64 on older hardware ran into was that they couldn't update to 8.1, because of these new requirements for additional CPU capabilities. Just tough luck I guess, although it is unfortunate for those running Windows 8 as MS requires an upgrade to 8.1 for continued critical updates.