but this error "failed to install bluestacks" many times ruin our experience with Bluestacks, many of US would have experienced this error while installing bluestacks [including ME]. well i found some simple solutions to this failed to install bluestacks error as below.
1) files/settings leftover from a previous installation, so clear up things with below tips
Delete Below things
B) C:\Program Files\BlueStacks
2) Cleanup old Registry keys with below file.