Laptop cannot display with higher resolution

Hello all,

I'm using Dell Inspiron N5010 (2010) with ATI HD 550v in Windows 7 SP1. Yesterday I bought Dell monitor E2414H (it can be display 1920x1080). I met some problems:

- I can't install monitor driver.

I try manually install in Device Manager but it still can't recognize monitor (although monitor connected).

- In my Catalyst Control Center, I can't set settings to show 1920x1080. Maximum is just 1280x1024. I try to check and uncheck "Use Extended Display..." then apply but nothing happended.

I recheck this problem with difference CCC version, it regconizes my card is HD 4650 (while the right is HD 550v), but I can set max resolution to 1600x1200. However still can't set to 1920x1080.

My driver to use for HD 550v is the newest version downloaded from dell.com. I think this driver doesn't support for 1920 x 1080.

Anyone know please help me how to fix that problems. Hope you can help me.

Thanks so much !