Windows stupid network problem...PLEASE HELP

It is a very very strange problem...after i install my win XP pro twice because of the same problem...i'm thinking to reinstall again...i have this copy of Xp Pro from 4 years never had this issue before...

The issue : internet explorer refuse to connect to my site to the hosting provider...to my C pannel control....and at some of the site(not all of them) that this hosting provider have in their database....i tried with firewall disable with antivirus disable ... this is very annoying thing...on others pc from the same network or outside the network these site ar working good .....if you click to go on the site...a few sec like 5-15 ..is thinking and then ...Internet Explorer cannot display the webpage...something is faultily here, i do not know what it is....i check may IP and DNS adress there are correct...

Please need a lot of HELP...i need to upload my site and it is impossible to connect to server....