Half life 2

i have Nvidya 7200 GS and playing Half life 2. But the game do not work properly. Frames are not smooth. Help me.
Answer #1
Try reducing the gameplay resolution/details, etc.
Answer #2
Try adding this to the command line parameter,in target line after exe" hit space and add this -heapsize 80000
Hit apply
-heapsize [Kilobytes]: This command tells Half Life 2 to allocate more RAM to the game system heap, where it can be accessed by the game to improve performance by storing more game information in RAM and hence reducing loading pauses
Optimum would be 1/3 to 1/2 available ram in Kilobytes…,need anymore help hit me with a pm