my pc configuration
asus-m2n68-am se2
amd sempron le 1250
2gb ddr2
windows 7 (32bit) ultimate(not genuine)
My problem is, sometimes when i boot my pc,the network status icon in taskbar shows an exclamatory sign in yellow colour and some text like this "no internet acces, unidentified network". But the Modem shows the green light. that means the net is ok. After a restart there is no problem at all. plz help me.

Remove the cable that goes from modem to PC, wait to task icon to gets a red cross (showing that there is no signal), plug it again, should work.

Happens to me all the time, seems that Windows is dumb anyway.

thanks RenanLazarotto,
let me try

Do what RenanLazarotto. It is an simpel and easy solution to most conenction problem.

First try to see whether other computers or laptops can connect to the same network wirelessly. If yes nothing is wrong with the network but with your PC instead. If not, you have to reset your network.

Reseting Router ( if you have one at home )

If you have a router. There will be a reset button at the back of it, use a pen and hold down the reset button for 5 seconds. After that your network settings has been reset to default try and see whether you can connect to internet. To change back your router settings go to your router control panel. You should have a link if not try this link

If you are totally sure nothing is wrong with your network but with your PC instead, that means some settings may be blocking it. Check whether firewall or other security softwares are blocking it.

At the same time, at the bottom of your screen, click on the network icon. It will open a new tab for you. Go to network sharing center ( something like that ) and try reconnecting from there to your network again.

This may seem an idiotic question to you but have you type in the correct password. Secondaly, can you connect using an ethernet cable?