First, is the popping and clicking coming from the recording process in the laptop, or could it be coming from the digital recorder? If you are not sure try connecting up a cd player to the laptop and see if there's still clicks and pops when you record.
If it's still present, make sure you don't have any programs running in the background you dont need, no screensavers, anti virus, power management should be off.
This may not make any difference, you could try altering the virtual memory so the min and max numbers are the same.
Go to the speaker icon on the task bar, choose adjust audio properties, then advanced properties then performance. Try adjusting the hardware acceleration, up or down, see if it makes any difference.
There could be many reasons why you are experiencing pops and clicks, it could be the built in soundcard, many of which are crap and introduce noise into recordings, seeing as you have gone to the trouble of making decent multitrack recordings, it's a pity you are going through the laptop soundcard, if you got the budget, go buy an external one, if the digital recorder has a digital out, get a soundcard with a digital in.
There's alot of narrowing down to be done before it's possible to say exactly what's going on.
I'd suggest you visit DellTalk, and look for audio queries for the latitude model you have, may find some answers there.
good luck
cp.