If the modem says Invalid SIM then its locked to another network and needs to be unlocked (see  )

No / Low signal: If the signal is weak, try changing ports and location.You could also employ some PC cooling techniques (see ) Ensure the modem is connected to a good port when in use then disconnected and removed when not in use. Overheating: The modem (and sometimes the PC) might overheat.

If you choose to use Wi-Fi then consider reading these guides and What are the problems commonly associated with USB modems?

Its still the internet connection series and in this guide, we’ll be discussing how to setup / install and configure a USB modem (ie MTN, Airtel, GLO, Etisalat etc) on your Windows PC.