Network connection keeps dropping, telling me "default gateway is not available".

Hi,

Step 1:

I would suggest you to follow the below steps and check if it helps:

a. Click Start. Type cmd in the Start Search box, and then press ENTER. 

b.At the command prompt, type the following command, and then press ENTER:

  ipconfig /all (there is a space between ipconfig and / )

  The ipconfig /all command displays Windows TCP/IP settings for all your network adapters.

c.If your IP address for your Local Area Connection is either 0.0.0.0 or 169.x.x.x (where x is any number), then your computer is not getting an IP address from the router. 

If that is the case, try this:

· ipconfig /release in the command prompt and press ENTER

· ipconfig /renew in the command prompt and press ENTER

Test it again by typing ipconfig /all to see what the address is?  If the address is still not correct (if you are on a home router, it should start with either 192.168.1.x or 192.168.0.x or 10.x.x.x)

Try updating the drivers for network adapter and check if it helps:

a. Click on start. In the search window, type Device manager.

b. Open the device manager and click on the drop menu of Network Adapter driver.

c. Right click on the driver and click on update drivers.

For more information, I would suggest you to refer the below link:

http://windows.microsoft.com/en-US/windows7/Wireless-networking-frequently-asked-questions

Step 2:

I would also suggest you to check for the issue in safe mode with networking and check if it helps.

View the section Safe mode with networking from the below article.

http://windows.microsoft.com/en-US/windows7/Advanced-startup-options-including-safe-mode

Step 3:

I would suggest you try to reset the router and check if it helps.

In addition to what Abdul said. If your router's DNS is corrupt or is just too full. Yes it can get too full. Then this often occurs. You can reset your router to dump the DNS cache by either just unplugging it from power source and Internet connection wait a few minutes and then reboot it. Or if it has an internal battery then push in a "Reset" hole on the back of it somewhere. Don't keep it pushed in cuz you'll have to reload the everything for it and reconfigure it. Just push it in and let it out. Make sure you delete all temporary internet files on your pc. IE does this in the Tools/Options. And Firefox does it in the Options. Personally I set Firefox and IE to automatically delete all cookies, files and everything upon closing. Chrome will do this also under the options. Or you could right click on my computer and click on tools and there should be an option to create more space on your hard drive which will get rid of all that. There's an easier way of doing this that I use but you really should know what you're doing before doing it. After you've done all this. Oh yeah, make sure before you do all this that the router is turned off and unplugged. And make sure you are not connected to any internet access point which I should say now to find an updated driver for your wireless card before shutting off internet and everything but don't install updated driver yet. After you've gotten rid of the useless **** the browsers save then this would be an awesome time to use those tools again in the my computer properties and use the defrag tool if you already do not have a third party one. After the defrag is done. Then install the updated driver. After the updated driver is done installing, shut down the pc. Don't do a restart like windows will ask you after the update, just shut it down. Then after the computer is shut down, then reboot our router/modem, and let it get completely online then boot up your computer. Now you should be starting from a clean slate. If you keep losing connection then either you've got adware/malware or virus or somebody is using your wireless access point and hogging your bandwidth. If you do not have a password for your wireless then put one on it. Usually if there is so much traffic thru a certain access point, it overloads the router/modem and of coarse you get booted off or whatever. Also, you are using an N grade wireless adapter. Is your router/modem N grade as well? If not then you're just wasting that extra bandwidth you could be using. If your router/modem is G grade then your adapter will only function in G grade. That means 54mbs compared to the potential of gigs using N grade.