Help!Macbook started running slow/beachball of death all of a sudden.What can I do to resolve?

Question

New to mac so don't know whats going on!Bought this macbook 2nd hand about 2-3 months ago.Its been running fine all this time,until about a week ago when the problem started.I get the so called beachball of death when doing the silliest of tasks,such as browsing the internet,opening files in photoshop,pretty much all the time.Once its there,its there for at least a couple of minutes.Ive tried using Activity Monitor to see if anything sticks out there,but theres nothing obvious.Tried repair disk in the Utillities.Ive had it come up a couple of times as I'm writing this!PLEASE HELP,SOMEBODY!!!!Macbook is late 2009,running latest Mavricks.
2.26 GHz Intel Core 2 Duo   4GB 1067 MHz DDR3  OSX 10.9.3 (13D65)

Answer 1

I managed to use the safe boot so my computer is now up and running. It looks  like Safari caused the computer to crash as I cant open it and every time I try I get an error message. Do you know how I can Safari to reload without loosing my bookmarks? Thanks
Process:    
Safari [810]
Path:       
/Applications/Safari.app/Contents/MacOS/Safari
Identifier: 
com.apple.Safari
Version:    
5.1.7 (6534.57.2)
Build Info: 
WebBrowser-75345702~2
Code Type:  
X86-64 (Native)
Parent Process:  launchd [105]
Date/Time:  
2012-11-26 21:06:43.071 +0000
OS Version: 
Mac OS X 10.6.8 (10K549)
Report Version:  6
Interval Since Last Report:     
316038 sec
Crashes Since Last Report:      
13
Per-App Interval Since Last Report:  2150133 sec
Per-App Crashes Since Last Report:   13
Anonymous UUID:                 
E5584CE6-35B6-4C0D-8543-65413FA53022
Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: 0x000000000000000d, 0x0000000000000000
Crashed Thread:  3