My older iMac is running super slow. I am thinking of completely clearing the harddrive and starting over. Will that make any difference? Overview stats: iMac (24-inch Mid 2007) Processor: 2.4 GHz Intel Core 2 Duo, Memory 2 GB 667MHz, running Yosem

My older iMac is running super slow. I've taken videos off and cleared some memory, but I continue to get the "beach ball" frequently and it stays on longer and longer. That memory clearing only helps for a little while. Before I did that, I took it in to the genius bar here locally about a year ago and they told me to be sure to restart it regularly (which I hadn't been doing), and I have done that. The only thing I can think to do is to back up and then completely clear the hard drive and start all over. Would that help? I know my iMac is older, but it's been a good machine and I would like to keep it going as long as possible. I am willing to take it in to get it worked on if necessary, but if I can fix it myself I'd rather do that. Any help would be greatly appreciated!

Heres the overview:

Running OS X Yosemite Version 10.10.2

iMac: (24 inch Mid 2007)

Processor: 2.4 GHz Intel Core 2 Duo

Memory: 2 GB 667 MHz DDR2 SDRAM

Graphics: ATI Radeon HD 2600 Pro 256 MB

Storage: 44.93 GB free of 319.21 GB