No desktop icons,start menu

Hello,
i have problems on my desktop and start menu they're all gone and its almost two months till now i can't retrieve it. I already do all the suggestions i get from the internet still nothing happens. I only able to access the internet and other program and files thru the taskmanager.
I already try to reformat my laptop, but after i turn it off the next time i use it again i encounter same problem.
what should i do? im using windows xp pack3, pentiumM , internet explorer 8