blinking projector image from Toshiba laptop

Last night I tried connecting my Toshiba Satellite A215 to a projector for the first time. The results were no good. Both my monitor and the projector's image blinked constantly. Adjusting the refresh rate didn't help. Switching to just one monitor -- the projector's -- didn't help either. I gave up, unhooked the projector, and showed the audience my presentation on the little laptop screen. Now I'm reluctant to bring this laptop to other presentations. Any suggestions?

I managed to resolve the problem in this way.
Go to Display Settings, then Advanced Settings then select the ATI Catalyst Control Center tab (if you don't have this tab you just need to download the Catalyst Software Suite from here http://ati.amd.com/support/driver.HTML) . Once you are on the catalyst Control Center tab click on the button to open the Control Center. From the left menu select Monitor Properties 1 -> attributes. Then go the lower right part called "monitor attributes", unflag the "use extended display identification data or driver defaults" flag, and select maximum resolution to 1200x800 and maximum refresh rate 60 HZ.
It worked for me I hope it does for you.