MacBook performance problems

My girlfriend is running a MacBook with a 2.1 GHz Core 2 Duo and 2.5 GB 667 MHz DDR2 SDRAM. She tends to keep a lot of programs open but she's getting really sloppy performance, way slower than a computer like this should get. Anytime you go to access the hard drive and or even sometimes just for the **** of it it gives you that little spinning wheel of death. I can trouble shoot a pc but I'm not really good with macs. Hard drive space isn't an issue. Can anyone recommend some next steps?

Download OnyX for her and run the maintenance routines. Read the directions first and always make a backup before you run a utility of this type. OnyX is free.

In addition to the advice already given, you can read Troubleshoot the spinning beach ball | Mac OS X | Macworld

If she likes keeping a lot programs opened then she might be maxing out her RAM and could probably use an upgrade. When her computer is going slow try opening up Activity Monitor and see how much RAM and CPU she has free. Also check out how much swap and page outs she has in the System Memory section.

Slowdowns can be due to several issues but depending how many programs she is using simultaneously that might be the cause of her problems. Does her computer run better when only use one program at a time? Does she forget to quit other programs when she's done with them? That's a common problem with new Mac users. 2 GB of RAM really isn't that much RAM for someone who likes to multitask with a lot of programs and if she got the slower 5400 RPM hard drive then we might have found the source of the problem.