Computer won't startup

[Scott D]

When I power up the computer, it says that the cpu fan is not running and shuts down. While this seems like a nice safety feature, the fan is most definitely running.
Is there a way to bypass this, and more importantly, a way to figure out why it thinks the fan is not working?
This is my Son-in-law's HP Media center computer. I can get more specs from him if I need to post those.
Thanks for any responses.

 

[Scott D]

I went and got the computer and brought it home. I bypassed the shutdown by hitting F2. And now rebooting doesn't seem to be a problem.
My question now is, should I worry about the aforementioned problem?

 

[Route44]

Test your power supply with a digital multimeter.