the other day i installed all updates listed on my software update list. when asked to restart my laptop the dock and my applications were missing. i sorted this out after a while and the dock and my applications reappeared. when i restarted again my msn had vanished. when trying to download msn again, nothing downloaded and instead would say 'mounting failed' when trying to mount disk image. now i'm trying to reinstall my t-mobile internet modem, and when trying to open the information on the disc that also appears as 'mounting failed'!! NEED HELP!! PLEASE!!! 
