How do you fix the laptop wireless problem when it is automatically disconnect and needs restart to work properly again?

it looks like issue of wireless card, in your laptop versus anything to do with the router, especially if the dropped signal is limited to the laptop. Make sure your drivers are update and if they are try reinstalling them.

If that doesn't work make sure that your wireless card is both sending and receiving packets (just go under network sharing and click on the connection, status box should come up and you should see number that represent both sent and received, they should be in the millions). If it is really low report back and will see if your DNS settings are correct  

 

Update the wireless driver, then restart the laptop. But first you have to make sure that your IP settings are default

start with updating your wireless driver if that doesn't work with you search this problem writing your laptop model like "lenovo t420 wireless disconnect problem" because some times laptops come with manufacturing problems and may need new patches.

Mostly this occurs by Wireless card drivers issue / May be the Card getting Loose /Damaged socket Inside.

..Update Latest Drivers 

Check the Laptop condition.. any Damages

 

it is a easy process to fix  it. first reinstall it i hope i will work properly

Reinstall the Wlan driver.

Mostly this happens because of Wi-Fi adapter issues. Try to upgrade the driver version that you've for your adapter. In some cases, due to virus attack also this happens.