How do I set the time on my pc permanently?

First of All, I must say Its very easy to do.

Yo will ask, So every time I start my computer, it shows me wrong time and the date goes back to 2011.
I have to change the time and date every time I start it.
 
How do i resolve this issue?

There are Many Ways in one to solve this problem 

Solutions

1. Before you replace it.
   leave the computer on for 24 hours,
   sometimes they will recharge if they are not faulty.
   if it works then you will not need to replace it. 
2. On your motherboard is a small rechargeable battery that is permanently charged up when the computer is on. It keeps your computer clock up to date. With a faulty battery the clock resets itself every time you turn off the computer.
   
   They are cheap items that are replaceable  
3. That is because of CMOS battery week or totally discharged. Try to replace with a new one, when system starts press F2 or Del key to enter in to CMOS Setup change your date and time, Save and Exit your system date time will be preserved until the battery goes down next time. 
4. Two things can cause that. One is a bad bios battery. Which is cheap and easily replaced. Look on your motherboard and you will see a battery that looks like a watch battery. Replace that and see if the problem stops. If not, run a scan with this and see what you find.  
5. Is it a PC or a Mac? If it is a PC, Double click on the clock. Kinda self explanatory after that. Make sure your Time Zone is right. 
6. Control Panel\Clock, Language, and Region set and date and SAVE