I am trying to connect my Tablet to my home PC Wi-Fi but every time I enter the Modem No. a small padlock icon appears on the Tablet screen preventing me from accessing the Internet... any tips etc.
Are you setting your tablet to use all upper case? On my Android tablet, you can set the typing mode to either initial capital letter, lower case, or upper case.
The padlock should just be showing that you've got a secure connection (which is what you want).
Try this;
Turn your router off.
Wait 2 minutes.
Turn your router on.
Wait 2 minutes again.
Search for the connection with your tablet.
Cross your fingers!