Icons and applications missing on HP PC?

I think my little boy has deleted something off my PC. It stopped connecting to the internet and on further investigation all the desktop icons have gone. Have tried system restore half a dozen times but it states it cannot restore from this point, so took tips from here and switched of restore point rebooted and swithched it back on, created a new restore point but it still wont work. When I first log on it tells me to install missing applications, but I dont know what is missing. I'm past my know how! Help!