my mac mini is slowing, spinning ball more frequent than in the past, do I have virus or malware?

Hello Paul,

Least likely is Malware.

Check the S.M.A.R.T. status of the drive in Disk Utilty by highlighting the Drive & looking at the bottom of the window.

Open Activity Monitor in Applications>Utilities, select All Processes & sort on CPU%, any indications there?

How much RAM & free space do you have also, click on the Memory & Disk Usage Tabs.

In the Memory tab, are there a lot of Pageouts?

See this FAQ on spinning beach balls. While it's unlikely you have a virus or malware, you could download ClamXav and do a full disk scan.

Right off the bat, looking at your page outs tells me you don't have enough memory for the tasks you run. OS X writes the contents of memory to the hard drive when it needs to free up space to run something else. Too much of this can impact performance. Guideline is that page outs should be no more than 10% to 15% of page ins. Yours is 60%.

And while I can't fond a 2GHz Core Duo, even the 2GHz Core 2 Duo can only use 3 GB of RAM, and whilst another GB of RAM will help, it won't totally alleviate your problem.