occasionaly i use my laptop in another room, but on most occasions i use my desktop computer, however, after not useing the laptop for a while, when i switched it on, i carnt get onto the internet as it keeps asking for the security key, i,ve tried all the passwords that i normally use, also the info on the side of the modem. If i plug the laptop directly to the modem it,s fine, any help would be wellcome!
You have a wireless router I assume ? Plug into the router and go to the wireless setup page, change the SSID and password and reset router. Change laptop network to use the new SSID and Password (add wireless network, structured).
Leaving a wireless network ad-hoc (no security), makes the router broadcast to all who can capture in range with nothing to stop them from accessing your router and setting exclusive rights to it as I said above (basically hijacking). Hiding SSID in settings is also good, although network will be detected they won't be able to know the ID even, much less the password. Good Passwords are 12+ digits with 2 capitals, 2 numbers and 2 symbols at least.