Laggy, scrolling and typing is rather slow

Hi,

Ever since I used the software update yesterday and installed the new update (10.5.8, not the snow leopard one), everything has been rather slow. Scrolling is slow, actions are slow, letters take longer to appear in a text box than usual.

I had thought it was also that I updated Firefox to 3.5 yesterday, however back in 3.0 like I was using yesterday, the problem is still occuring, and isn't just in Firefox, it's any application I use on my Mac

Is anyone else experiencing this?

Firefox is very laggy for me, particularly on proxied servers. Firefox seems to have trouble making bookmarks, freeze for 5 seconds when loading an image, and often crashes. I have now moved to Opera. I suggest you take a look at some other browser too.
I have done some research, and I found out that in 2008 users reported laggy typing and poor mouse response after an update. Apparently the solution was this:

We need to first shut down all bluetooth options (turn all bluetooth settings to OFF by unchecking them, including any options that might be on under the advance tab), then second reset the PRAM. You can do this by shutting down and booting up again. AS SOON AS you boot up, hold the COMMAND OPTION "P" AND "R".

Click to expand...

This may not work in your case as this was an old update, but give it a shot anyay.

I appreciate your suggestion, but Opera is as bad as Internet Explorer in my book. Can't stand the thing. I use Firefox over Safari simply because of the web coding add-ons that I can use in Firefox.
Then as I said, this isn't just limited to the web browser. It happens in any application on my Mac.

I have never switched Bluetooth on, so that's not the issue.

Ignore the bluetooth. Did you reset the PRAM?