Tried that . Correcting in BIOS makes no difference.
I have however noticed that for a split second on the desktop after botting it shows the correct set time then goes back. Which suggests something is loading and doing the dirty work.
Also AVG is now picking up a trojan PSW Legendmir.EYY on boot up to desktop - which goes into the vault - and soemthing called 5640.exe which a quick Google tells me is very suspect. I have now disabled System restore and will run AVG in safe mode but it wil take some hours -