MID tablet will not boot up

[mike0liver]

I own a MID (Chinese) tablet serial No. m799ca running Android 2.2. It has been idle for several months and when I tried to boot it up I got the Android logo flashing slowly and this then changes to an error message: "System is damaged, please try recover from external storage". There appears to be no factory reset hole in the casing, I have tried holding the "Volume+" and Start buttons and releasing when the Android logo appears but this does not help. I do not know what "external storage" is being referred to.

I don't want to throw the equipment away until I have explored all avenues to try to resolve the issue - can anyone help?

Cheers,
Mike