avast free won't install on windows 7 enterprise

[alfonsine]

Hi,
my new avast free download won't install on windows 7 enterprise.
I tried to install it on my second hdd it didn't work, so I tried to install it on my first system drive. It always says that I have to restart the the system because a previous
installation wasn't finished. I read that I have to uninstall microsoft mse 4.1 , so I did. But it still won't install.
Does anywone know the reason?
thanks

[Staticguy]

Before you had MSE, what antivirus did u have on your operating system? Norton or McAfee or etc antivirus? Use their own removal tool to remove any files related to it and run the removal tool on safe mode.