Dell Vostro 1000 Does Not Detect My Wi-Fi

Dears,

I have Dell Vostro 1000, Windows7 32bit installed.

Problem: Sometime it does not detect my default WiFi connection.

Action have been taken: I rename my WiFi connection in router then its appear in laptop connection list, after some days it does not recognize it and I have to rename again in my router to appear in laptop connection list. Although other connection that are in my surrounding are appear in my connection list.

Any idea guys.

Thanking in advance.