Slow computer?

[lr20]

I recently got a MacBook this summer (I'm in college) and for the most part, it's been working fine.

However, a few weeks ago, I've been having a problem with the computer; specifically, I can be typing in a word document or surfing the web (note: this most often happens when surfing the web) and all of a sudden, the mouse will turn into the little "rainbow ball" and the entire screen will freeze. This can happen for as short as 5 seconds to 10 minutes (in the longest case so far). I'm able to move the mouse around, but the rainbow ball does not go away, and I am unable to click on anything within the application I am using. (If I try to activate another application, the whole computer will usually freeze for a while).

Around the same time this began to happen, I also noticed that videos (ie. on youtube) have begun to take forever to load, whereas before it would take 2 to 3 seconds.

Is there something wrong with the computer, or is something else (eg. the network or server) coming into play here? Do I have some form of malware? (I don't think there are any viruses for OS X. YET.) And most importantly, is there any way to fix this annoying problem?

As a former Windows user for 8+ years, any expertise and advice is most welcome.

[Doctor X]

If you have not "cleaned" you computer in . . . like . . . forever, then you may wish to run maintenance scripts--clean caches, et cetera.

Seeketh the freeware Onyx or the shareware Cocktail.

--J.D.

[lr20]

I downloaded Onyx and rain a few maintenance scripts (thanks for the suggestion), but while my computer is running a little faster, I am STILL being bombarded by the silly rainbow ball thing.