I have a Fujitsu Siemens
Whenever you can't connect to a network it is rarely the computer that is at fault, especially if it has been working.
Step 1, however, is to turn off your modem, router, and computer for 10 to 30 seconds, then turn on the modem and router (often the same unit), then the computer. If the computer is connected to an Ethernet cable, make sure you see lights on both ends of the cable, on the router and on the computer, if not, unplug and re-seat the plugs.
Step 2, If step 1 did not resolve the problem, bring up your command line on the computer. In Windows, click start and type cmd then hit the enter key or Win+R, type cmd and hit the enter key... this will bring up a command line tool. In Linux, find the terminal app.
Step 3, in the command line tool, type: ipconfig (ifconfig if you are using an Apple or Linux product) and hit the enter key.
You will be presented with a list of items, look for your IPV4 IP Address. Your IP address should look something like 192.168.0.048. If the first number is 169 you are not connected to any network. Look for a default gateway and write down that IP address (usually 192.168.0.1, but could be something like 10.10.0.1)
Step 4, type the command ping 192.168.0.1 (use your gateway address). If you get replies back from that, you are able to talk to your router.
Step 5, type the command ping google.com. If you get no replies back, your internet service provider is most likely down, and you should call them. It could also be that your DNS server is not properly configured in your network settings, but if your computer WAS working, it should still be OK.
Step 6, If none of the above solves your problem surfing the web with a browser, then your browser may have been hijacked, you will want to run a couple of good anti-malware utilities to find out. I use two to solve most problems: HitManPro (www.hitman.com) and MalwareBytes (malwarebytes.org)
on Oct 25, 2017