Installing Python 3.4 after Un installing Python 2.5 in Windows

I am trying to install Python 3.4 on Windows 8 after un-installing Python 2.5.

I installed Python 3.4.1 - x86 msi package and during that process it never gave a prompt of Remove/Repair/Change Python that usually pops up if there is previous version already installed.

I used x86 version as I wanted to use NumPy too and it supports this only.

I chose "install for all users" option but in my Registry -HKEY_LOCAL_MACHINE-> SOFTWARE->Python-> PythonCore it is showing Python2.5 not 3.4.1

Though Control Panel lists only Python 3.4.1 as active program.

Also due to this I am facing problems in installing NumPy as it shows error of "can't create key" during installation.

Also after searching for possible problems in stackoverflow site itself I tried below commands in cmd prompt.

C:\>assoc .py

.py=Python.File

C:\>ftype Python.File
Python.File="C:\WINDOWS\py.exe" "%1" %*

C:\>assoc .pyw

.pyw=Python.NoConFile

C:\>ftype Python.NoConFile
Python.NoConFile="C:\WINDOWS\pyw.exe" "%1" %*

Please tell how to solve this.