MacBook Pro Suddenly Lags...

Hello Everyone!

I could do with a little help from the Mac gurus here. I am more PC oriented and this issue is baffling me.

My MacBook Pro, 13inch Mid 2012 has started to lag after booting. It boots in good enough time but main operation and shutdown is being hampered by intermittent lagging. Opening programs and even typing an email on Gmail is slow. The spinning wheel often comes up and The keyboard has to "catch up with me" The shut down process has also lengthened. It is taking up to 23 seconds to shut down when normally it has taken just up to 10 seconds. The problem started with no software or hardware changes, out of the blue.

The system has been upgraded with: Crucial M4 SSD, 8GB Corsair Memory and is running with all the updates. I updated the firmware in the SSD and have just started running the TRIM enabler in the last few moments. I reinstalled Mac OS yesterday (via CMD+R) thinking the issue was a software one but the issue still exists.

Does anyone have any idea what is wrong? I have a genius appointment set for tomorrow if all else fails.