After boot display blinks infinite times [VIDEO available]

[Infamosus]

Hi dear Insanelymac fellows.

 

After successfull installation of SL (10.6.6.) it worked like a charm for months.

My hardware specs are below.

 

Eventually, after one of the boots, it went bad in some hard-to-describe behaviour. I suspect that in last successful boot, I'd played with 'Monitors' settings, refreshing screen resolution for attached as second monitor TV.

 

The situation is as follows: after boot, it shows desktop (autologon on) for a several seconds, after that it goes to blue, than to light blue, that to desktop again and so forth. Can do this for hours, nothing changing.

I recorded short video here, to give you an idea of what's going on.

 

My backup snow leopard installation works fine. Windows works fine. So it shouldn't be a hardware problem.

 

Please help me, in which direction I should start to investigate an issue?

 

Thanks in advance

 

 

 

 

HW: Gigabyte GA-EP45T, Gigabyte Radeon HD5870 (0x6898), 4GB DDR3, CPU C2Q 9450

[jtp.redson]

Boot into single mode by pressing '-s' at chameleon and then mount your boot volume using this

 

/sbin/fsck -fy

/sbin/mount -uw /

 

and then cd to /Users/Home(or your UserName)/Library/Preferences and look for com.apple.preference.displays.[long number].plist or something like that and delete it (or you can back up all of them and delete all preferences)

 

Also cd to /Users/Home(or your UserName)/Library/Caches and delete all caches too.

 

Reboot and let me know.

Hopefully it works.