無網際網絡存取問題 ( BB100)

近日經常有'無網際網絡存取問題 ', pc 攞唔到ip, 已換了router同lan card 到唔係時時得.
請求各位ching幫手,thx so much.

Equipment List :

1 x PC, 2 x wireliss device, 1 x NAS
Router : Cisco WRVS4400N + 1 x Linksys Giga Switch
BB100 copper wire only