Everything's running slow

Question

My MacBook Pro is running slow.....it starts up a little slow, but the real problem is starting up applications, closing apps, surfing the net, etc.
In Safari, I've reset it, cleaned up history, cache, cookies, etc but it's still running slow. Sometimes it doesn't even connect to my WiFi. I have to turn it off and restart.
If I have iMail or iPhoto open, opening any other app is brutal. It lags.
Everyday, the pinwheel spins without conclusion so I usually Force Quit a lot. This can happen 3-4 times per day regardless of the app I'm working on (Excel, Word, Type Pad, Safari, iTunes, anything!).
In a nutshell, I think I need some sort of monitoring/cleaning software (maybe a virus??). But Google is just unhelpful with it's 3.6 Billion recommendations.
Can you recommend the Gold/Apple Standard? I don't mind buying the software if necessary. I just want my beloved MacBook Pro to function like it did when I first bought it. Needless to say, if you think my problem is something else, I'm all ears. I have no idea what else it could be so if you could help a newbie out, that would be great. :-)
Thank you.

Answer 1

Try cleaning out your start up items.
Apple Menu > System Preferences > Accounts > Login Items
select the item you wish to remove (click on its name and then hit the "minus" button at the bottom of the list.)
Turn off Universal Access, Bluetooth, Speech Recognition, and Internet Sharing if you don't use them
Apple Menu > System Preferences > Universal Access/Bluetooth/ Speech Recognition
This will save you some valuable RAM and processor resources.
Turn off the Dashboard
Open the 'Terminal' Application.
To turn Dashboard off:
defaults write com.apple.dashboard mcx-disabled -boolean YES
To turn Dashboard on:
defaults write com.apple.dashboard mcx-disabled -boolean NO
You have to restart the Dock after making either change for it to take effect:
killall Dock
The Dashboard uses RAM to refresh widgets etc. By disabling it, the RAM used to update Dashboard can be used on Applications.
Clean you Hard Drive
Mac OS X  uses the free space on your hard drive as "virtual memory", and it depends heavily on that virtual memory to run efficiently. If you're Mac feels sluggish, it may be because your drive is too full.
Erasing useless files (Reset Safari, Empty Trash, Erase Documents/Files you no longer use)
Yes, there are many applications out there to do this for you.
I use CleanMyMac. Many people say that cleaning Applications are bad for you mac, but I disagree.
Clean My Mac has erased 20.48 GB of files that I do not need. Caches, History etc.
All of the above have worked for me.
Good Luck