System hang's & nothing works

I install opensuse 11 GNOME 2 days before with pre-installed windows xp, i install it in 40 GB partition installation successful without any error.but now when i am using suse after 5-10 minutes system hangs mouse not move nothing works and i just restart my system.after that suse opens fine but same problem occurs all time,no problem while using xp. please help me to find what i am doing wrong.

SYSTEM CONFIG.

  1. HDD 500 GB SATA (40 GB for xp,40 GB for suse).
  2. RAM 512+256 DDR1
  3. MOTHERBOARD D101GCc
  4. intel pentium 4 processor 3.0 GHz

Sounds like possibly a display driver or a memory chip problem. Have you installed the driver for your video card from the repository?

For graphics card, see: HOWTOs - openSUSE

For a memory tester, use one found on the Ultimate Boot CD