No internet access appears often on Realtech wifi pci card.

In this case the ISP issued router/modem is the most likely problem.

I believe you should try to start up in safe mode with Networking to see if the problem persists when in safe mode.

It may also help to try connecting to a different router and see if the problem persists.

You could also try using a static IP which may help with the handshake problem you seem to be having.
- Click Start Button
- Type: ncpa.cpl
- Right click the Wireless Adapter and choose PROPERTIES
- Click and highlight the Internet Protocol TCP/IP Version 4 option
- Click the Properties button
- Choose “Use the following IP address”
- Enter the following for the IP address: 192.168.1.xxx- the xxx should be an address that is outside the range of DHCP on your router.

Enter the following for the Subnet Mask: 255.255.255.0
- Enter the following for the Default Gateway: 192.168.1.1
- Choose “Use the following DNS servers”
- Enter the following for the Primary DNS server: 192.168.1.1
- Enter the following for the Secondary DNS server: 8.8.8.8
- Click OK
- Click OK
- Reconnect to the wireless signal