Unknown lag during Bf2 gameplay

Ok to start i play Battlefield 2 and its the only game that challenges my computer. When im play on multiplayer i get a lag that makes my guy keep walking in a direction i didnt mean him to go. Same with tanks and aircrafts ect.. I have cancelled out that its not my internet connection because i disconnected it while playing in single player and it continues to get the lag.
I am pretty confident that it is not my video card because ive turned the setting all the way down and with the video card i have it shouldnt be a problem. I have 2 sticks of ram that equal out to 1gig, and i have tested both sticks seperatly while playing in game and both had same result of a good run and bad run. I jsut got a new fan for my processor to keep it from overheating. I jsut can think of anything in my computer that is causeing this problem. Ive been told it could be my videocard overheating but i dotn know how to test that and people have said the processor could be burnt out and iam not sure how to check that, because if it is melted and had a problem my computer would shut down, right? And the last odd thing is my computer would beep alot at me when id click to many things while its lagging.

Motherboard:MSI Ms-6702
Prossesor: 64AMD 3200+(not overclocked)
Videocard: radeon 1600 512mb
Memory: 1gig (2 half sticks)

 

Have you got the latest video drivers installed?
And have you got the latest patch on, 1.3 it is - 1.4 is available as a beta which you could try.

 

iam pretty sure i do but ial redownload them but u got ne other ideas what wrong?