I was having problem installing the latest v4.1.2 as it was having issue after I start it it shows my old blank project, so things I did were,
Caution: Please move your sdk and projects to a separate location before following steps if you haven't. So it might save your time downloading sdks and stuff.
1- Uninstall old Android Studio Completely (from Contorl panel -> Programs).
2- Delete this Android Studio Folder located at C:\Users<user_name>\AppData\Local\Google
3- Delete this Android Studio Folder located at C:\Users<user_name>\AppData\Roaming\Google
4- Delete these folders(.android ,.AndroidStudio*, .gradle) located at C:\Users<user_name>\
After doing all this I was managed to have fresh updated Android Studio v4.1.2