"advanced system care" is a piece of junk that damages machines.
Sounds to me like you need to backup, restore to defaults and start again without the crap software
PS - the Win7 machines that Dell currently offer are actually often licenced for Win8....but are "factory downgraded" prior to sale by Dell. Its how M$ are artificially inflating the numbers of Win8 machines in circulation - they're counting licences sold, not machines with the software on......