Normal things that can help you:
- You have a PPPoe connection then you won't have any problems because all the settings are inside the modem and your internet will be working through LAN connection but it is not recommended because of security reasons.
- I like using a WAN connection to connect but here the things become difficult for newbies as assigning new setting is not easy they have to do many things like giving certain values and other things given by their ISP.
- This thing applies to a wireless router also so you can apply it too.
- First check the brand of your modem which you can easily find.
- Open their site and check if any new support installation is required by your device as it can be easily told by them.
- Disconnect the connection and now simply disable all the application which are running in background.
- Turn off your PC because this is required.
- Keep your device plugged in for electricity and remove all the plugs which are connected to the CPU because it may have current.
- Now get a pen(It should a nice Tip of almost 0.5 mm) .
- Now see the back of your modem there will be a small hole just right or left to your on/off button as it may be located there because in mine it is there.
- Now when you will find the hole take the Pen inside the hole and you will feel that there is a button which is right , now keep it pressed for almost 15 seconds and in any case the Pen is removed again try.
- Now you will find that your modem's configuration is set to default and there will be all the things new which you will need to input in order to use internet.
If you are having in assigning your setting kindly comment so that I can help you as I have done that thing many times.