OSX Mountain Lion Finder slowly dies, system becomes unresponsive - restart required to

I have a MacBookPro retina and it was working fine for months but all of a sudden its now started to fall apart every few hours. I use my computer daily for work and when i first boot up everything runs well but over time, say 2 hrs, i notice that screenshots take ages to appear on my desktop and then finder doesnt open and even new web pages or new applications do not load. I try restarting finder, but that doesnt help forcing me to restart my computer, which i sometimes need to force restart as it hangs on the grey screen.

Things I have tried that have not worked

- re-installing Lion

- removing the 'All my files' bookmark from finder

- uninstalled air display (which registered some 3rd party kernels)

I have noticed that my mac never finds my backup timecapsule, so i will try turning off timemachine entirely.

Help!!!

p.s. I kinda miss my 2009 Macbook pro with Snow Leopard, still going strong and has had a fraction of the issues i have experienced with my new retina and OSX lion combo.