Even before looking for the driver it is important that you install Service Pack 1 for stability; we can't be sure but it might even resolve your current issue.
If this is for your Dell Inspiron N5010 then your Dell drivers should be
HERE.
On the Dell site there are 8 drivers listed under "Verkko" but the only one I see that says WiFi is:
Intel Intel(R) WiFi Link 6300, Intel (R) WiFi Link 6250, Intel(R) WiFi Link 6200, v.tic: TRWFW0986D, A02
which is from April 12th, 2010 so unfortunately that may actually install the NETw5s64.sys dated March 18th, 2010 that you already have.
You might try getting a newer driver straight from Intel
HERE