Mitchell A is quite right, deleting the duplicates may causes the system problem, but I warn you that it is unusual to witness that each programs in Program Files has its duplicate in Program Files (x86). In my computer, only the program accompanied with windows 7 have their duplicates (WMP...
First, you should check your privilege, your current account may not be the administrator so you cannot make changes. Then if you still cannot fix the problem, you scan your computer to check the presence of virus.