Please follow the below steps ;
Check and confirm whether the system clock is set right (including month & year).
Check and delete if you find any other security software in C:/program files and common files.
Run the update tool from http://download.mcafee.com/products/licensed/cust_support_patches/MSCPRXFIX.exe. and restart the computer.
Click update in security center . Do report back if you face any issues on the same.