404 errors and SEO not working

Hi,
i am having problems when a user tries to create an account or login it gives me a 404 error.
Also the SEO links dont work, can someone please help.
Thanks

forgot to mention this is the link it get directed to for registering

http://playfreegameonline.net/user/register/

ok i just realised the .htassess file wasnt copied correctly from the previous owner. I have asked him to send it to me, i hope he has it backed up

check your inbox 

Super!!! thanks a million