|"I think I may have a cooling problem in my Motion Computing Tablet LE1700"|
What do you mean, you think you have a cooling problem? Either you do or you don't. And the only way to know for sure is by monitoring the temperature. Which CPU do you have & what are the temps at idle & under load? From what I could find, you probably have a C2D L7400, if that's correct, the max temp is 100C.
"Can I use the fan and/or heat sink from the LE1600 to put in the LE1700?"
It's difficult to say without seeing them.
"Got some new Kingston memory from NewEgg"
The C2D L7400 runs at 667MHz FSB so the correct RAM would be DDR2-667. Is that what you got?
"I did a MEMTEST and it seemed to also point to probable memory problems"
As I said with the cooling, either you have a problem or you don't. If memtest86 is showing errors, the RAM is most likely defective. Did you test each stick individually & then both together? Did you try switching slots?
"Could I have gotten some bad memory?"
It's possible. You need to confirm it's bad by running memtest86. If you get consistent errors, contact Kingston & have the RAM replaced under the lifetime warranty.