Issues concerning Google Analytics module

Hello,

All the problemes started when I tried to copy and paste the tracking code for Google Analytics. I was receiving an error something like header information; I look on internet for solving it and the problem was caused by white spaces; I checked the file Google_Analytics.php using Notepad++ but everything was fine.

Then I deleted the file and as a result the module was missing (in admin -> Extensios -> Google Analytics there was nothing, not even an add button). So, using a ftp client I upload it again and now I receive this error when I click on edit edit button next to the name of the store in Google Analytics module page:

Fatal error: Class 'Controlleranalyticsgoogleanalytics' not found in /home/raldesig/public_html/lafoisor.ro/system/storage/modification/system/engine/action.php on line 36

How do I reset this module to default?