After much research I found the dell webcam driver and Creative Webcam Central software to open your webcam on Windows 7 64bit for Dell Studio 1749. I upgraded from Vista 64 bit to Windows 7 64bit and could not find how.. this is how:
You need to download these drivers
LCCH_0330_DRV_LA_1_12_01.exe webcam driver
and Dell R230103 driver.