One other thing to try as well before even doing the A&I is to repair permissions through Disk Utility. You can even do a repair on the drive when booted up from the installation disc by using the Disk Utility from there (you can't repair a system drive with Disk Utility if you're booted from it, BTW). To take it even further, you might want to run a tool called
OnyX and run some of the maintenance script options included there.
Also, if she's got less than 10% free space on the hard drive, this might be the root of all her problems. Mac OS X usually likes to have no less than 10% free space on the hard drive available.