jak spustit hru pod minimalní požadavky

Dobrý den
mám hru left 4 dead nic moc kompa
potřeboval bych od vás radu hru spustím ojeví se my menu atd...
tak dám hru jednoho hráče a vyberu si jakou chci kampan a když dám 1 misi tak se mi to v ukazkách sekne ale když dam třeba 2 misi tak jako začnu hrát ale když se třeba rychle pohnou (třeba nahoru dolu) nebo je tam hodně nepřátel tak se mi to zase sekne tak vás chci poprosit jesli neznáte njaké programy na zlepšení vykonu atd...

tady jsou minimalní požadavky hry a muj pc

CPU
Minimum: Pentium 4
You Have: 2 processors running - Intel(R) Pentium(R) 4 CPU 2.80GHz
PASS
CPU Speed
Minimum: 3 GHz
You Have: 2.80 GHz Performance Rated at 4.20 GHz
PASS
System RAM
Minimum: 1 GB
You Have: 511 MB
FAIL: Sorry, your computer does not meet this minimum requirement. You may be able to add more RAM which could make your computer more powerful. Click the 'We Recommend' to see how.
Operating System
Minimum: Microsoft Windows XP / Vista / Vista64
You Have: Microsoft Windows XP Home Edition (Build Service Pack 32600)
PASS
Video Card
Minimum: 128 MB, Shader model 2.0, ATI 9600, NVidia 6600 or better
You Have: ATI Radeon X300/X550/X1050 Series (ATI Radeon Graphics Processor (0x5B60))
PASS
Video Card Features - Minimum attributes of your Video Card

Video RAM: Required - 128 MB , You have - 128 MB
Video Card 3D Acceleration: Required - Yes , You have - Yes
Video HW Transform & Lighting: Required - Yes , You have - Yes
Vertex Shader Ver.: Required - 2.0 , You have - 2.0
Pixel Shader Ver.: Required - 2.0 , You have - 2.0

Video Card Driver Version (DirectX)
Your driver version number is: 6.14.10.6912
FYI: Your video card driver version is provided for your information, but it is not part of this analysis. But proper video card driver versions are important to the proper operation of your product.
Sound Card
Minimum: Yes
You Have: Realtek HD Audio rear output
PASS
Sound Card Driver Version
Your driver version number is: 5.10
FYI: Your sound card driver version is provided for your information, but it is not part of this analysis. But proper sound card driver versions are important to the proper operation of your product.
Free Disk Space
Minimum: 7.5 GB
You Have: 25.7 GB
PASS
ja vim nic moc komp ale rodiče my nechtěj koupit novej :(