It's because the monitor cannot handle the frequency/resolution from your
new display adapter.
- go to command line (ctrl-alt-F2)
- edit /etc/X11/xorg.conf
- In section device change driver to nv
- in section screen subsection display change modes to more conservative
mode like 800x600 or 640x480

hope that helps

OOT : are you from Indonesia? Seems like Indonesian name to me.

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