When I play certain "new" PC games my computer freezes up and the game lags real bad. What are some good games that are fairly new that fit these requirements?

Operating System
Windows XP Professional Service Pack 2 (build 2600)

Processor
1.60 gigahertz AMD Sempron
128 kilobyte primary memory cache
256 kilobyte secondary memory cache

Main Circuit Board
Board: C51MCP51
Bus Clock: 200 megahertz
BIOS: Phoenix Technologies, LTD 6.00 PG 10/18/2005

Drives
160.04 Gigabytes Usable Hard Drive Capacity
86.07 Gigabytes Hard Drive Free Space
_NEC DVD_RW ND-1300A [CD-ROM drive]

Memory Modules
960 Megabytes Installed Memory
Slot 'A0' has 512 MB
Slot 'A1' has 512 MB

Display
NVIDIA GeForce 6100 [Display adapter]
Video Graphics Accelerator [Display adapter]
COMPAQ MV940 [Monitor] (17.7"vis, December 2000)

Sound
Realtek AC'97 Audio

I doubt ALL this information is needed but I included it all jsut in case.
Thanks!