The performance issues and the failure of applications are all due to insufficient memory, aka. missing swap partition. Due to the hardware failure your N900 right now is limited to 256MB, that is alarmingly low memory for maemo to run at all.
If you do not replace the missing magnet, this is just a slightly enhanced brick...

There is no software solution, you may look for some hardware specialist near you or Nokia Care to get the damage repaired.

well this mean the missing magnet has no relation with work or not of external memory card because i told you that after that someone flash it i lose the sign of memory card on fone .........
also there's no nokia specialist here are all amateurs ,,that someone who i took it to him one of them instead he try to fix internal memory insufficient by software flashing he break the memory card
only thing i want is how i can flash it by myself through usb cable and meomo flasher and get back the version rx .10.2010.10.19.1.pr combined 003
because i got always no device suitable found when i try flash emmc or error *m when i try flash fiasco
any suggestion ?

my internal memory now its like 455.5mb
total siz:455.5mb
in use by system:227.8mb
user files:226.3mb
available:1.50mb
12kb contacts
1 kb other files
and i have install something like cutetube,cutetube-qml, uttorent etc

for God's sake man.
Instead of taking photos of N900s screen , just take a screenshot.

much easier. your N900 has it integrated

screenshoot man that is its work? but this n900 cant get even a file has 1 kb in system or let say nothing work in it even note ,camera everything
just app manager and file manager and empty partition u understand