You may want to ask the previous Admin if he/she done anything to corrupt the File System(libraries) or Kernel.
A sign of this is if the system takes a long time or hangs to bring you to the console login screen after booting init or hangs after you try login in w/ your user/pass.
Is the Disk space %100 capacitated!!!
You should take a look at the syslog messages, history commands, and importantly boot log.
Try booting into runlevel 1 single user maintainance mode!!!
Check for Memory leaks also - "free" , "vmstat 1" , "top".
You may want to back up "tar -zcvf" your config files on a seperate partition and reinstall the OS on the root partition.