so the cable connection is OK - the wireless isnt?
either you've messed up the config - look in network | connections
one of them should be wireless connection
right click - status - what does it all say?
(look at available connections - can you see yours?)
disable enable and repair the connection
recycle the router.
open a command prompt
type ipconfig /all
what do you get?
it should look something like ...
Description . . . . . . . . . . . : Intel(R) PRO/Wireless
Physical Address. . . . . . . . . : 00-xx-xx-xx-xx-xx
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.100.13
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.100.254
DNS Servers . . . . . . . . . . . : 192.168.100.254
what EXACTLY do you get?
it's not impossible that the wireless bit of the router has just died ....