Dell Latitude E5400 - Interupting WLAN signal.

Anyone -
I have a Dell E5400 Latitude that is about 5 years old.
I have recently had the computer suddenly shut-down.
I was told by a freind that it may be dusty and over heating. Afterwards, I vacumed the back side of the laptop around and over the vents. I have now only had it happen 1 time today.
the real reason for that background is to continue on to discuss my wifi signal and possibly probelms with my wlan card.
Over the last 3-4 days, i have begun to loose my wifi signal to the point that it is off more than on and i'm having problems performing my work. I have experienced this at public wifi, my office and at home. I assume that I'm having a problem with the driver or the card itself.
I have deleted the driver several times planning to re-install it, but then when i re-boot the computer, some driver in the archive is being accessed and the system is reloading the non-funtioning systems. last, occassionaly my keyboard has begun to lock up recently. any ideas that would tie these together or even just help on the wifi issue.
thanks.