Did you make certain that you installed the correct
drivers/firmware?
You need drivers that are for Windows 7 and for 32 or 64 bit depending on what you're using.
If you don't know whether you have 32 or 64-bit, just go to the start menu and right click on Computer. Click Properties and you'll find a page describing your computer it will tell you whether you're using 32 or 64 bit about half way down.
For some odd reason I cannot get the Samsung support page to work properly, but here's a link to your computer on Samsung.com. Just click on the downloads link to find your drivers.
Here are links to the drivers for your computer with the type preceding them.
http://www.samsung.com/in/support/de...sub_class_cd=P