Ubuntu 11.04 screen flickers

I am using ubuntu 11.04 and recently updated via Update Manger, after which my screen flickers. Sometimes it stops after few mins but again starts.
dj@dj-Aspire-4315:~$ sudo lshw -C display
  *-display:0
       description: VGA compatible controller
       product: Mobile GM965/GL960 Integrated Graphics Controller (primary)
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 03
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:44 memory:fc000000-fc0fffff memory:d0000000-dfffffff ioport:1800(size=8)
  *-display:1 UNCLAIMED
       description: Display controller
       product: Mobile GM965/GL960 Integrated Graphics Controller (secondary)
       vendor: Intel Corporation
       physical id: 2.1
       bus info: pci@0000:00:02.1
       version: 03
       width: 64 bits
       clock: 33MHz
       capabilities: pm bus_master cap_list
       configuration: latency=0
       resources: memory:fc100000-fc1fffff

Reading other related threads :
Solution 1:
- untick the box of "screen dimming when idle" --- Didn't work for me
Solution 2 :
 Service Manager -> Uncheck "Detect RANDR (monitor) changes"-- Where is this in 11.04??

Help please