Error starting mongodb

I have installed mongodb in the following directory.

C:\Program Files\MongoDB\Server\3.4\bin

Next I set up a path variable and this

C:\Users\Theodosios>mongo --version

gives me

MongoDB shell version v3.4.3
git version: f07437fb5a6cca07c10bafa78365456eb1d6d5e1
OpenSSL version: OpenSSL 1.0.1u-fips  22 Sep 2016
allocator: tcmalloc
modules: none
build environment:
distmod: 2008plus-ssl
distarch: x86_64
target_arch: x86_64

So far everything works well. Now I want to install a test database in the folder

C:\Users\Theodosios\Desktop\NodeJs_Coursera\Week2\mongodb\data

However,this confuses me. I enter in this folder

mongod --dbpath Theodosios\Desktop\NodeJs_Coursera\Week2\mongodb

but I get this error.

2017-04-16T18:27:21.584+0300 I CONTROL  [initandlisten] shutting down with 
code: 100

How can I fix it?

Thanks.

via Theo