Like Veilo I have now been able to get into the game finally. After reloading Arma2 OA and reinstalling DayZ mod from scratch it still didn't work..I then realised what you guys were on about (penny dropped moment). I then jumped onto a server that was running 1.7 beta version and bingo...straight in and with colour and sound and movement..yippeee. This explains why I got in first day then mysteriously couldn't replicate that. It was because I must have been jumping in the 1.6 version servers.
Anyway, the damn game was at night again so I only stayed in for 15 mins then logged out. I am now ready to party..... Dead Z's everywhere
Lesson, make sure you have the right version for the right server...doh