First of all go to My network places And right click the mouse button then click properties then a new window display that show the your Lan card connection right click on that an click on their property option...that show a new window which have many option ......click on tcp/ip an click on their property in it if u connected with server then obtain automatic IP address if u r connected individually then fill manually ip address then click on OK.an again OK....now goes to my computer right click here and click on the property here if your computer name is same then change it if different then OK . It should be always advisable than your computer have different name but have same group name,click OK,it will ask u to restart your computer,restart this,if u check the connection is establish or not then click on start and then click on run type ping and the computers ip address u want to check for eg...ping 192.168.0.1 press enter
go to start->control panel->network connections->local area connection->properties(Right click)->tcp/ip->use manual ip and assign address.
If u do not get help from above details then use this link
http://support.microsoft.com/kb/306126
