Error installing postgresql 9.5.14 on windows7: “unable to write inside temp environment variable path”

Hi,
I have already tried what have been suggested online but nothing worked.I tried this solution:https://www.youtube.com/watch?v=h6HRGFJvzzw I also tried to enable WSH via http://1stopit.blogspot.com/2011/01/postgresql-83-and-84-fails-to-install.html but all this did not solve the problem, still getting the same error.
I am running as administrator and anti virus is disabled.
Can you please guide how to fix this issue?
Thanks and regards,
Abhinav Srivastava
My bitlock installer log is as follows. OS is windows 7 (64 bit)
Log started 08/17/2018 at 00:59:05Preferred installation mode : qtTrying to init installer in mode qtMode qt successfully initializedExecuting C:\Users\Abhinav\AppData\Local\Temp/postgresql_installer_2b07efb6c7/temp_check_comspec.bat Script exit code: 0
Script output: "test ok"
Script stderr:

Could not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 Data Directory. Setting variable iDataDirectory to empty valueCould not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 Base Directory. Setting variable iBaseDirectory to empty valueCould not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 Service ID. Setting variable iServiceName to empty valueCould not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 Service Account. Setting variable iServiceAccount to empty valueCould not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 Super User. Setting variable iSuperuser to empty valueCould not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 Branding. Setting variable iBranding to empty valueCould not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 Version. Setting variable brandingVer to empty valueCould not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 Shortcuts. Setting variable iShortcut to empty valueCould not find registry key HKEY_LOCAL_MACHINE\SOFTWARE\PostgreSQL\Installations\postgresql-x64-9.5 DisableStackBuilder. Setting variable iDisableStackBuilder to empty value[00:59:08] Existing base directory: [00:59:08] Existing data directory: [00:59:08] Using branding: PostgreSQL 9.5[00:59:08] Using Super User: postgres and Service Account: NT AUTHORITY\NetworkService[00:59:08] Using Service Name: postgresql-x64-9.5Executing cscript //NoLogo "C:\Users\Abhinav\AppData\Local\Temp\postgresql_installer_2b07efb6c7\prerun_checks.vbs"Script exit code: 1
Script output: CScript Error: Can't find script engine "VBScript" for script "C:\Users\Abhinav\AppData\Local\Temp\postgresql_installer_2b07efb6c7\prerun_checks.vbs".
Script stderr: Program ended with an error exit code