After reinstalling Windows, did you install the chipset drivers as the first drivers installed after the reinstallation.  The chipset drivers must be installed first, otherwise Windows will not be able to properly recognize or install drivers for many other devices, especially those integrated on the motherboard. 

Steve

i uninstalled all drivers and installed chipset drivers the first time..And it did not work again..Can you give me chipset drivers link??Maybe i found another one..Thank you...

http://support.dell.com/support/downloads/download.aspx?c=us&cs=19&l=en&s=dhs&releaseid=R58370&SystemID=INS_PNT_P4_9100&os=WW1&osl=en&deviceid=1134&devlib=0&typecnt=1&vercnt=1&formatcnt=1&fileid=70519

 

i downloaded from that one before you said to me..and i installed chipset drivers the first one from all drivers..and tried it but the computer can not see the ethernet..so i could not connect the internet..but all dirvers are working..but i have an idea..if i format again,and i install chipset drivers the first..is it work??when you send me that message i installed all drivers..and when i saw your message,i uninstalled all drivers..and installed chipset drivers the first one..must i format again to uninstall all dirvers succesfully???