It's not that difficult -- just have steady hands and patience as to not scuff anything up.
http://letmegooglethatforyou.com/?q=...ke+apart+guide
Yes, 2GB is the max RAM. If it's a Core 2 Duo, then I believe you can shove 4GB in there (2 x 2GB).
As for the fan issue, did you reinstall OS X when you took possession of the computer, or are you using the OS X the original owner installed? Did he, perchance, install SMCFanControl, which allows the user to set the minimum fan speeds?