iMac recently slowed up

Hi there, I'm a fairly new mac user (bought iMac in 2010) having been windows all my life. I have an iMac running Mac OS X version 10.7.4 with a Processor 3.06 GHz Intel Core i3 and 4GB memory 1333 MHz.

Everything has been fine until the last week when each time i try and do anything I get the spinning rainbow symbol, even if im on Firefox and switching tabs.

I have not downloaded anything recently and my hard drive is only half full. I have repaired the permissions which hasn't changed anything.

I'm happy to upgrade the RAM but thought I'd better check to see if there was a problem first.

Any advice would be greatly received.

Mark

There are several things you can do to determine what's causing the slowdowns and spinning pinwheel. First, run a health check on your hard drive by booting your iMac to the Recovery partition. (Hold down command + r keys)

Once in Recovery, use Disk Utility to verify your hard drive. If the hard drive is OK, the next step is to run a cleanup and maintenance program. The only one we recommend and one that is safe to use is OnyX (free) which you can download from here. Make sure you download the version for Lion not Mountain Lion. Read the help file and follow directions to use OnyX.

Hi thanks for the reply.

I'm not sure if i managed to get to the recovery partition, it just loaded to my usual logon page. I have a wireless keyboard could that be why?

I have downloaded and run OnyX and still have the same problems

When you ran OnyX, did you allow it to verify your hard drive?

Verify structure at launch? Then yes it did...

Any other suggestions?

Try this. Open System Preferences > Startup Disk > make sure the lock is OFF > Highlight Your Hard Drive and click on the Restart Button. Sometimes Mac needs to reset the drive.

I think I've managed to fix it.

I reset the PRAM

On reboot I held down Alt+Cmd+P+R and everything seems OK for now.