Don't know what you mean by "refreshing the pc", but with such little other info, makes it almost impossible to give you help. Still, here are some things to try:
1. Did you install the necessary drivers for your Network Interface Card (NIC)?
2. Have you checked Device Manager for any signs of missing drivers?
3. If the problem is specific to WLAN, have you tried using an Ethernet (Cat5, Cat5e, or Cat6) cable?
4. If problem is specific to LAN, have you tried going wireless?
5. Is the WiFi radio turned on?
6. Are the network adapters disabled?
7. Have you tried the loopback test?
8. Are there other devices that have internet access while on the network in question?