Upgrading my iMac Leopard

[Simple Living]

I have Leopard and am wondering what the latest version is that I can upgrade to. I've never, ever had a single problem in all the years that I've owned my iMac but have recently begun having problems playing videos on certain sites like Vidxden. I never had a problem before but, no matter what plugin I install now (or new version of DivX), it keeps telling me I'm missing a plug in. Also, for the last week, Firefox stalls every half hour and I have to restart my computer to get it working again. (Is this an internet connection issue or Firefox?)

I have the recent free versions of Perian, QuickTime, WMV, Flash Player and VLC (and my software updates are current) but these aren't correcting my playback problems. I tried downloading the newest version of Java but, as I understand it, it's incompatible because of the age of my computer. ???

Have I gotten to the point where upgrading is useless and I need a new computer to keep up with the newest software? I hope not. A new computer is out of the question. I don't have many programs running on my computer because I use it for basic surfing and watching videos only.

Any suggestions? Anyway to do the equivalent of a Disk Defrag, maybe? Oh, and I have removed everything DivX from my computer so that's already done.

Model Name: iMac
Model Identifier: iMac7,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 1 GB
Bus Speed: 800 MHz
Boot ROM Version: IM71.007A.B03

 

[GGJstudios]

I have Leopard and am wondering what the latest version is that I can upgrade to.

The current version of ML.

You can find specs on all Apple products, including maximum OS by visiting EveryMac.com
You can also get specs for your model by entering your serial number here.

Anyway to do the equivalent of a Disk Defrag, maybe?

With very few exceptions, you don't need to defrag on Mac OS X, except possibly when partitioning a drive.

About disk optimization with Mac OS X

You probably won't need to optimize at all if you use Mac OS X.

If you're having performance issues, this may help:

Performance Tips For Mac OS X​

 

[Simple Living]

Thanks for responding. Unfortunately, I'm not the most computer literate person so I'm not sure what to do with the information you posted. If it's helpful, here's the link to the specs of my model: http://support.apple.com/kb/SP16

 

[Simple Living]

I just checked my free space. I have 86% Free Space available so that can't be an issue. Anyone else have any suggestions?

 

[Simple Living]

Performance issues aside, can anyone please help with my upgrading question? I'm assuming this is necessary if I can't download the latest version of certain software, like Flash. It only allows me to download Adobe Flash Player version 10.3.183.48