Studio 1558 Over Heating??

I have a dell studio 1558 i3 core processor 4gb ram 500gb hard drive windows 7 home premium.

When doing a regular virus check I noticed that in the full scan my laptop was just abruptly shutting off. So I did a search and several people had issues with their laptop over heating. So, I downloaded Speed Fan to see what my laptop temperature was running at.

Just leaving it sit, and not doing anything my laptop temps are:

HD0: 111F
Temp1: 80F
Temp2: 32F:
Core 0: 108-118F
Core 1: 100-102F

I do not see a drop below that.

If I put on a movie that's stored on my hard drive it will jump between 125-137F. I've had the laptop about 4 years. It is probably dusty inside no doubt ( I have 5 cats and live in a rural area), but looking inside I don't see a terrible amount of dust, but then it's hard to see through the vent holes at all.

If I take out the battery the fan seems to run less and the temps stay around 106. But even watching a movie the temps spike up to the same temps.

I've tired blowing out the fan from what I can do with an air can. But this doesn't seem to cure the issue.

I've looked in the System Event Log and for the times it shut off, I did get an event 37. And this was the error message:
The speed of processor 0 in group 0 is being limited by system firmware. The processor has been in this reduced performance state for 71 seconds since the last report.


Just wanting some input as to if this a fan issue, whether it needs to be just cleaned or what. And how much does a cleaning run usually? Or if they have to replace the fan?

Thanks!

Yes I do live in the US

Mel