lag while playing pes 2013

[Microsoft]

hi
i used to play the game without any problems on xp sp3
after i have installed windows 7 home basic
i experience lag while playing
the game when i first start it runs smoothly
but when the first half is about to end it starts lagging
the lag increase as long as i play until it becomes very annoying
i have :
Intel(R) Pentium(R) 4 CPU 3.00GHz x 2 ‎(3.00Ghz)‎
2.5 gb ram
ATI Radeon HD 5670 1gb ‎(PS3.0/VS3.0)‎ (gpu)

thanks in advance

 

[Chalky Emultion]

I think your CPU could be the problem, because it's very weak. Pentium 4 processors are not really good to run Windows 7.
If you can, upgrade to a cheap Core 2 Duo CPU, or to a Pentium D (if you have a socket 775 motherboard).

Try lowering all graphics settings and set your anti virus in game mode, if supported. Try also disabling your anti virus when playing and close any other program to save CPU load.