Why is my Mac so slow now?

slow system performance can be caused by failing hard drive, you may want to back up any important files just in case

One thing you might try is OnyX, which is a swiss army knife of disk utilities. Many have found that this helped with their systems slowing down. It's at: http://www.titanium.free.fr/pgs2/english/download.html . Do the tasks in the cleaning and maintenance tabs.

How much free disk space do you have? You want 10%+ of your hard drive free for systems usage, less than that can really slow things down.

In the activity monitor, under system memory, what's the page ins and outs values? If outs are high, compared agains ins, the system is spending alot of time swapping memory to the hard drive, which impacts performance.

For free space, I have about 1 GB DDR SDRAM.
Page ins/outs: 527380/152675.

The SDRAM is the amount or memory your system, which is different than hard drive space.

When you highlight your hard drive on your desktop, and hit the Apple and I keys, how much space is available? Or, click the blue apple, about this mac, more info, ata, and choose your hard drive.

While zero page outs is optimal, 10%-15% or less of page ins is normal. Normally, the system writes a page out when there isn't enough physical memory to handle current needs - doing too much of that impacts system performance. The value your system shows says you could use more memory for what you run.

For memory I have Capacity: 93.04 GB
Available: 69.06 GB

You have a large hard drive, with not much on it, if 69GB is available. So it won't help to archive anything off the hard drive - there's plenty of space for the system to work.

The only way to reduce page outs is to buy more memory. If you have one 1GB ram today, you could put another 1GB RAM in. If you have two 512KB ram today, you could replace one or both with a 1GB ram strip. Recommend Crucial at http://www.crucial.com , Kingston (not their valueram line, though) at http://www.kingston.com , or Samsung which is sold through distributors (I've used OWC at http://www.macsales.com).

Some other things to do ....

Have you run OnyX yet?

Have you run the Apple hardware test, or either of the TechTool programs, to ensure your hardware is OK? Insert the original OS X disc that says in small print on the label 'AHT Version x.x'. Reboot holding the option key down, choose the Apple hardware test, click the arrow to the right, follow directions, and choose the extended test. Does it tell you anything?

Boot from your OS X disc, holding the C key down, which will boot from the disc instead of the hard drive. Off the menu bar, bring up disk utility, and repair disk (can repair permissions too, although you can repair permissions when loaded from the hard drive too). Any issues identified?

When you have disk utility open, what does it say for the SMART status?

Good news! Glad to hear it's running well. You might want to run OnyX every once in a while, too.