I'm always having intermittent connection. What could be the problem?

A few things to do to find out what is the actual problem to this issue:

1. Check the physical network connection
2. Do a ping to the router to check for local network connectivity
3. Do a ping to the internet to check for internet connectivity
4. Check whether your PC is able to resolve a domain name into IP address

1. Check that the connection to the router is ok. Change the cabling if necessary (For wired connection). Or,
check the signal strength that your wireless adapter receive from the wireless router (For wireless connection). Move to somewhere nearer to the router if necessary to get a better signal strength.

2. Ping to the router's IP address to check the local connectivity.
A successful reply means local connectivity is OK.
A failed reply means something is wrong between the communication of your PC and the router. Please check or re-configure the router's setting if necessary. Make sure your PC is able to receive an IP address from the router, or you may also try disabling and re-enabling your network adapter.

3. Ping to a known Internet IP address (such as 8.8.8.8) to check the Internet connectivity.
A successful reply means you have no problem connecting to the internet.
A failed reply means your router is unable to connect to the internet. You may have to re-configure or restart the router if necessary.

4. Once you are connected to the Internet, try opening a browser and try opening any website to see if your PC is able to resolve the domain name into IP address and opens the webpage.
If unsuccessful, try typing in the IP address of the webpage into the URL field of the browser and try to access the webpage (E.g.: try http://209.85.132.104 to access to Google).
If successful, it means that your router has problem with the DNS service, try restarting the router or configure a static DNS server address for your PC.