i think my switch has no stacking module instead! thanks for your help! 

not in stack!

i did upgrade and downgrade both the latest and the old ios versions but nothing worked, it still rebooted spontaneously!sing driver version 4 for media type 1Xmodem file system is available.Base ethernet MAC Address: e0:89:9d:ba:d3:00The password-re...

I think so but i dont know which version was there before upgrade!