My dell laptop won't connect to my router anymore. Please help

Hello,

I have a Dell Inspiron N4050 with Windows 7 that I have been using for a couple of years now with my router and faced no issues.

However, after coming back from a holiday, I found that it isn't connecting anymore. I tried troubleshooting and it suggested the problem is that the security settings have changes. The current security type on my router is WEP and the saved security type on my laptop is WPA-personal. I can't change it because the WEP option isn't present on the the list of security types on my laptop.

All of my other devices wouldn't connect straight away either. After I chose the 'forget network' option, and then connected to it as a new network, it was ok. But there's no 'forget network' or any other similar option on the dell.

Any help would be greatly appreciated.

Thanks in advance!