I got the "Open Tray" problem on my out of warranty Xbox yesterday, Micro$oft would fix it for £100...
... Then I found this on youtube... tried it... and it worked :-)
(I also find standing it on its side and shaking it works !.. )
Still cannot believe how unreliable these Xbox's are.. whats this?... my 8th Problem ?... had 5 replaced by GAME; 2 sent off and fixed (for free) in Germany and now this... rubbish !...