Laptop screen goes blank after recovery from Sleep Mode
 

First off, it's a SONY VAIO VGN-FZ180E and I'm running Vista 32-bit.

In the last couple of months, I've started encountering an error - the
screen goes blank upon recovery from Sleep Mode. Don't remember exactly when
it started, and couldn't use System Recovery to roll back that far anyway.
The only workaround I've found is either restarting or closing/re-opening the
lid. The "Turn off monitor" in "Power Options" is set to "Never", by the way.
And my nVIDIA graphics card driver and ACPI driver seem to be current.

Any suggestions on how to fix this? Thank you so much!