MacBook Pro :: Unresponsive When Opening Certain Files

I haven't had too many problems with my MBP. However, beggining yesterday I've had a very unresponsive computer. The problem only occcurs when I open certain types of apps. Google chrome (which i am using now) is perfectly fine, photobooth, even imovie is working fine and not making the computer unresponsive. However, when I try to open safari/software update/firefox/skype the computer always (100% of the time) will have a long stream of unresponsive time, followed by a small time frame where the computer catches up to any commands I pushed (force quit option), which is than followed by another stream of unresponsive time.

I've had the activity monitor out while I tried opening safari or software update and it will show an 8% usage. Nothing remarkably high. however the programs will be highlighted in red with the words unresponsive and it will occasionaly make the other programs (like google chrome or finder) unresponsive.

I know that iMovie is a very heavy taxload program for the MBP but if i can use that smoothly, I think it's safe to say my MBP is not too "slow".The only thing in common I see between the programs that provoke an unresponsive computers is that they use the internet (safari/software update/skype/itunes will log onto the store). Whats peculiar is that google chrome is working great.Does google chrome connect to the net in a different way?

Heres my mbp details:
MacBook Pro (10.6.8) 
Model Identifier: MacBookPro6,2 
Processor Name: Intel Core i5 
Processor Speed:  2.53 GHz 
space free is over 70 GB 

Info:
MacBook Pro, Mac OS X (10.6.8)