I have an old laptop (HP Elitebook 8470p), with the OS being MS Windows 7 Ultimate.

The wifi symbol has a red cross on it. Hence I am unable to connect to any network. So I looked online for the solutions, and I opened the Windows Mobility Center and there I found that the wireless option was greyed out [Please refer to the attached image], hence I could not turn it on. I tried doing the fn + function keys, but no luck. There is no function key for the wireless option on the keyboard.

Please help and provide a step-by-step solution.

not connected. you can see a red cross on the symbol
after troubleshooting,
the option is greyed out