Vista Laptoop can not get Router's IP Address

Hello,
My Vista Laptop is connected with internet (Reliance Broadband) through a d-link DIR 300 Router. It was working fine. but for some days it can not detect Router(IP Address showing some other address). and it is showing unidentified network and can not be connected with router. I tried make it static then router is connected but not the internet. I tried with the wired connection but then also it can not be connected. the problem surely in my laptop.I tried to release renew reset the ip but failed.
Other computers through the router is working fine

Please advice