Q: wireless in macbook 9.2 usually does not detect home wifi

Care to share which OS you are using?

Please detail ALL you have done so far in the way of troubleshooting?  Need this info to avoid the been there done that scenarios.

It is very depressive and irritating

Then use the ethernet & your Magsafe.

If you have AppleCare, call them.  Let them deal w/it.

OOW:  Take your Mac to your local Apple Store or an AASP.  Diagnostic testing is FREE!

Other options:

How to save money on Mac repairs with your credit card’s extended warranty

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Try the basics first:

  Change your router channel number.  Most times this works & is all you have to do.

Disconnect & reconnect your modem.  unplug it for about 10 seconds.  Plug it back in.  Do the same for Apple’s routers.  Wait for everything to reboot.

System Preferences>Network

Click the Assist Me button.

In the next window that pops up, click the Diagnostic button & do the necessary.

Research Knowledge Base for network problems that pertain to the OS that is currently installed on your computer.  See these basic networking KB Articles:  http://support.apple.com/kb/HT1401 AirPort troubleshooting guide

http://support.apple.com/kb/HT4628  Wi-Fi: How to troubleshoot Wi-Fi connectivity

http://support.apple.com/kb/HT2712 Using network locations in Mac OS X

Manually provided DNS server addresses are higher priority than DHCP's

http://support.apple.com/kb/HT1714 Solutions for connecting to the Internet, setting up a small network, and troubleshooting

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What to do when you can't connect to the Internet

Also, run the Airport Utility app which is located inside the Utilities folder.

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If using a  Linksys router, contact LinkSys Customer Support and/or post in their forums.

If using Apple's Airport, please re-post over in one of the AirPort Forums.