Well so far as switching distros, I started with Ubuntu. I hated it more and more every day. My current use of Fedora is a result of a several-month-long journy of testing nearly every distro I could get my hands on (well the ones that I liked the specs for anyway).
distrowatch.com was my friend to say the least. For some reason I just kept coming back to Fedora, I dont know why. I tried the standard distro first, then the KDE spin and I'm currently using the LXDE spin. I really like it, especially the fact that it has a system usage monitor right on the main panel along with 1 click access to the terminal and the file system. Now that you guys mention it though it MAY be an overheating problem. The whole reason I experiment using my laptop is because it's notorious for overheating (it's a 3 - 4 year old Compaq with ALL the vents on the bottom) to the extent that I think some of the hardware may be heat damaged (I've recorded the temp of the processor at 200 degrees F before) I'll have to try it using a cooling pad and the default hardware (gods know I could have messed up in the transition somewhere). I always assumed it was some id-10-t error on my part or something in the programming that wasn't connecting quite right.