I can't install the intel chipset driver and i have no sound after reformat?

You need to go back to Dell. If the computer came to you from them new. Use the serial number on the back of the tower. It is also on the bottom on a tag. Let them scan you. On multiple driver downloads Dell will send a driver download manager, driver reset tool, and crash ysis tool. These will stay with you for the future. Look at the details of the downloads. You may have to type a path. Jot down the information correctly and follow it to the tee. The sequence is important. I experienced this also and learned quickly. My PCI device was not seated correctly and caused the "no sound". Took the screw out of the rail and wiggled it around, replaced the screw and had sound. Hope it helps.