If you are unable to install the Windows 8 preview then here are some possible reasons:
[ul]
[li]You are using Windows 8 Enterprise, you won’t be able to install then. Microsoft will release ISO files later.
[/li][li]The language of your Windows 8 installation is not among the 13 initial supported languages.
[/li]
[li]For 64-bit installations of Windows 8.1 Preview, your CPU must also support CMPXCHG16b, PrefetchW and LAHF/SAHF.
[/li][/ul]
Possible fix:
lace and rename the MSU file in an easily accessible place, e.g. C:\8preview\preview.msu
2. open command prompt in administrator mode.
3. Type: Expand –F:* c:\8preview\preview.msu C:\8preview
4. Type: DISM.exe /Online /Add-Package /PackagePath:c:\8preview\Windows8-RT-KB2849636-x64.cabReplace the “x64.cab” on the end of step 4 with -x86.cab" for 32-bit versions and “-arm.cab” for RT versions.
Your text will be corrupted in the Windows 8 store for the 8.1 download page on restart, but the Windows 8.1 preview should download once the servers become less overloaded.