You have to use DC Unlocker software to unlock ZTE MF190 dongle.
Download software to unlock ZTE dongle click here
i. First of all, if you use memory card, remove it. remove sim card, and put SIM card what you want to unlock.(it will display invalid sim)
ii.Plug your modem in to your computer,sometime connection manager will display, close it
iii. Unzip what you download and open dccrap.exe
iv. First select the manufacturer as ZTE datacards ( No: 1)
v. Select the model as Auto detect (recommended)(No : 2 ) If you know the model and which com port you use.u can do that way also.
vi. Click find button (No: 3) . after your modem model will display below box
vii. After detect modem click unlock button (No: 4 )
Cheers... you have done. After few seconds modem will unlock.
Restart your computer and use your modem.This connection manager also working for this. If you want to use ZTE connection manager click here to download.