I have a mid 2007 iMac with 3g of RAM and is otherwise stock from Apple. For the past few months, I have noticed my iMac is not running as smoothly as it used to. I have used Tech Tool Pro to see if that may help, but I haven't noticed a difference. I am wondering if installing more RAM would work and/or a bigger hard drive. Any other programs I could try to "clean" things up? Should I reinstall the entire OS and start from scratch? Any help would be great. Thanks.