OpenServer and node.js

In your case, you probably do not have the node_modules folder in the domains / landing Gulp does not start, there are no files in the node_modules folder, the treatment is to restart the installation if there is a file package.json domains / landing G

npm install -g npm install gulp 

node -v
npm -v what is your version? as the gulp command launch comes from ROOT

 X: / openserver / domains / your-domain / node_modules also here 

 X: /openserver/domains/your-domain/gulpfile.js also here 

 X: /openserver/domains/your-domain/.gitignore also here 

If you use also openserver - create your-domain as a domain

Show me files in domain / site url

show me the screenshots!