If you had a virus and have problems like:
VIRUS ALERT! message in your clock
Missing Hard drives in your My Computer
Missing items from your start menu:
Download combofix
Run combofix after disabling your antivirus if you have any working with real time protection enabled.
http://download.bleepingco mputer.com /sUBs/Comb oFix.exe
Download smitfraudfix
http://siri.urz.free.fr/Fi x/Smitfrau dFix.exe
restart to safe mode, assuming that combofix will fix your safemode issue and you will be able then to restart to safe mode.
Run Smitfraudfix and press 2 to clean your PC