Why would I experience this lag?

[Crafty]

This could be a hard one to fix and I certainly have no idea how to fix it. I will try to explain the problem I am experiencing the best I can. I have two games I like to play on my computer. One is a flight simulator named Black Shark, and the other a battlefield 2 mod called project Reality. I have just recently installed the flight simulator, Black Shark, but have since started to have problems with Project Reality. After I have played the game Black Shark and started up Project Reality, I am experiencing what looks like a lag. It’s like playing the Black Shark game has had effect on Project Reality. The only way I can play Project Reality now, is by using Acronis, (which is a hard drive backup software) to keep placing my computer back in time to a point that I didnt play the game Black Shark game. I do know that the Black shark simulator is quit cpu demanding, but I am not sure that this would cause this problem. Other things I have tried , is to reboot my computer after playing Black Shark. Specs Listed below.
1)   Motherboard: Asus Crosshair
2)   Cpu: Amd dualcore 3.21 ghz
3)   Memory: 4 gig
4)   Os: windows vista 32bit home
5)   Hard drive: Western Digital 600 Gb 16 cache
6)   Sond card Audgy
7)   Graphics Card Geforce 260 gtx

[kuszmania9999]

have you run any error check and defrag the HDD?how much space left?

[Crafty]

have you run any error check and defrag the HDD?how much space left?

How do I run an error check? When I try to defrag it says that the Hard Drive doesn't need a defrag.

[snakey-111]

http://support.microsoft.com/kb/315265

[Carbon Dudeoxide]

How do I run an error check? When I try to defrag it says that the Hard Drive doesn't need a defrag.

Defrag anyways. Trust me.

You may want to follow my guide here:
http://www.computerhope.com/forum/index.php/topic,62253.0.html

[KingPincer]

If your experiencing some lag maybe it is a problem with the video card. Does your games have met with the system requirements?

[Crafty]

If your experiencing some lag maybe it is a problem with the video card. Does your games have met with the system requirements?

Yes it's a geforce 260 gtx

[KingPincer]

I'm not good when it comes to video cards but what kind of video card would fit for games like this carbon?

[Carbon Dudeoxide]

The 260 GTX is a pretty high-end card. I am pretty sure it's not the problem here.
I also don't think a disk check is necessary.

One thing I would like to know is when did the problem start and if there are any error messages?

On top of that, follow my speed-up guide and check to see if your computer can run the games with this website:
http://www.systemrequirementslab.com/referrer/srtest

[kuszmania9999]

I'm not good when it comes to video cards but what kind of video card would fit for games like this carbon?

its in  here

http://www.digitalcombatsimulator.com/index.php?end_pos=718&scr=default&lang=en

http://bfnation.net/bf2/sysreq/

you video card

http://www.nvidia.com/object/product_geforce_gtx_260_us.html

seems like you pass everything, there a prob with the pc.

[Crafty]

This started when after I installed and played the game Black Shark, it's a flight Sim that is quite demanding on the CPU, but I get around 25 to 40 fps which is what other people are getting who play this simulator. I myself feel, after playing this game Black shark, that it has somehow carried something over into the other game and has affected it - Do you think this is possible and if so what would be the cause? Thanks!!

[Carbon Dudeoxide]

Not sure what the problem may be, but you haven't exhausted your supply of suggestions yet.

[Crafty]

Thankyou for all the advise guys, but unfortunately the problem remains the same. I have narrowed this down to the best of my ability, but to be honest this is now driving me mad. Can someone here please explain this >Why after installing and playing another game would it then affect another game? What part of this process would cause this?