Can't reset pram on my iMac

[Oblivion2500]

I have been trying to press cmd+ctrl+p+r when turning on my mac before the white screen appears. It does not seem to work. It does not do a second chime or reboot or anything at all! I have mac os x lion 10.7.3 and iMac 27" late 2009.

Any help would be great!

 

[Oblivion2500]

Oh! I figure it out! I was pressing ctrl+opt+p+r instead of Cmd+ctrl+p+r.