Hi Flowers
The "rainbow ball pops up" could mean so many things and not necessary adware related. What do you mean by "you computer is stuck". You can't open any application? Have you checked for potential hardware errors (
https://support.apple.com/en-ca/HT201257)?
Also just to make sure 10.6.8 is the latest version you can go to ? I believe Mac OS X v10.6.8, can Upgrade to OS X Yosemite for free.