Programs wont open in new ibook! help

[Rena Bella]

Well my ibook, which I got in October has been great up until now, but since last week it has been causing me a lot of problems.
For an example, it start loading REALLY slow so i found it that was cause of a whole bunch pf corrupt files I downloaded, but Im not even sure how to fix that.

Now, my addressbook refuses to open! I click on it, and it loads, but nothing ever opens, even though my dock shows me that its is open...WHAT THE **** ISGOING ON?

[Macman]

have you a. repaired permissions. b. deleted preferences for the offending apps. c. installed lots of new fonts(which would account for the slow loading), or d. installed any new software or hardware since the problem started?