Problem with the Internet, works for 3 min & later it shows No internet connection in Aspire c24-400

If this is your private home network, then you need to check a few configurations.

First and foremost is your computer’s network config. Are you one DHCP, the setting that gets its setup from the router? If so, you need to check and see IF you’re getting anything from the router.

If I put quotes around something, it’s to show what you type or should see. Don’t use the quotes when running a command.
If you’re in Windows, go to your search box and type “cmd”. Don’t hit enter. On the right, you should see “cmd.exe”. Right click on that, and “run as administrator”.
You’ll get a black box with a cursor.
Type “ipconfig” and hit enter. This will bring up a listing of settings. One will be your current WiFi or ethernet connection. You should see an IPv4 address something like “192. 168.xxx.xxx” or “10.xxx.xxx.xxx”. The “x’s” are numbers that differ from computer to computer. The numbers that I do show are the most common for home routers. If you see something like “169.154.xxx.xxx’, that’s called an APIPA, and it’s an IP your computer gives itself if it can’t find a DHCP, and it hasn’t been manually assigned. This is so your computer can connect to other computers connected on a peer to peer, without a DHCP/centralized network. If you have this kind of number, it means you’re not connecting to the network at all. Check cables if you have them, make sure you’re WiFi is on, etc…
If you see a number like the ones I’ve mentioned as common, then type “ipconfig/all” and hit enter. Scroll until you come to your IP address. Check to see you’re on DHCP (DHCP Enabled? Yes/No). If not, then you are manually configured, which could make sense. Write down your IP, MAC, and subnet mask. We go into the router next.
If DHCP IS enabled, you’ll be going into your router anyway, so bear with.
Every router is different, so I’m only being general here. If you don’t know how get into your router configuration, you’ll need to get someone who knows.
Log into your router.
Check your list of devices and see if your MAC address is listed. If it is, you may have limitations set. If it isn’t, your IP may be incorrect.
Look for your LAN setup. This will tell you 1. what network settings you need, and 2. if there’s any restrictions on DHCP.

But, just to make sure, check that your IP address is within your subnet parameters, and that the subnet mask is the same. Most home users should have something like “192.168.0.1” and a subnet mask of “255.255.255.0”.
If that’s what your router says, but your computer is something like “192.168.0.10”, (ok), with subnet of “255.255.0.0” (not ok), your problem is the subnet. I can’t go into a lot of detail here, because there are a lot of details, and a lot of possibilities. If it doesn’t look right, you need to either learn what is, or hire a professional. Having an incorrect manual IP configured can be deceptive since Windows will give you a connected indicator, whether or not it’s actually connected.
Another type of restriction on my router is that I maintain access control. That means I have to manually allow every device that wants to connect.
There’s also a whitelist/blacklist. A white list is if you want to limit your browsing ONLY to the listed locations. A blacklist is if you want to prevent browsing the listed locations. However, if you can use the internet with other devices, this isn’t it.
Your browser also has a white/black list, and it’s specific t each browser. If you have your whitelist turned on with nothing in the list, then you won’t be able to see anything.
Now, if none of the above items haven’t fixed the problem, there’s also a matter of “proxy servers”, which is something of a redirect for your browser or computer to connect through another server. If this is set when it shouldn’t be, or set incorrectly, this will also cause a failure. This, you can google.

If all else fails, try buying a USB WiFi adapter (better than the cheapest, but not really expensive). Plug it in and bring up your taskbar networks icon. The new WiFi adapter should be in the dropdown or listed. Try connecting to your WiFi with that. If it does work, it could be an issue with your original adapter.