Bf4 PLEASE HELP- really low fps

Hi, I've got a Windows 7 computer with Ati Radeon HD graphics card. I've installed the latest amd driver update and still my bf4 has bad lag.
Right now it does around 15 fps which is not very good.
These are the things that I've done already to try improve it
-un-parked my cpu cores
-updated my graphics card.
-installed .net framework
-DISABLED ORIGIN IN GAME
-repaired the game in origin about 10 times!!!!!!
-uninstalled it and reinstalled it
-installed amd gaming evolved

I've also put all my settings in the game to low.

My computer specs are

Operating system- Windows 7 home premium 64-bit (6.1, built 7601)
System manufacturer- compaq-presario
BIOS- Bios date 01/07/10 11:37 ver 5:17
Processor- AMD Athlon 2 x2 215 processor 2 cpu's - 2.7GHz
Memory- 4096 Mb Ram
DirectX version Direct X 11

I've done all these things and still it only has 15 fps. Why???!!!
I don't want to upgrade to windows 8.1.

What can I do to make it so much better??