on start up fans run 5 sec then stop then repeat

Hi all, need a little help.
When I start my computer the fans come on for 5 seconds or so then everything stops for a few seconds and then it happens again, and again and again ad nauseum. The dvd drive lights blink as they normaly do on start up.
For some months it has taken until the 3rd attempt to complete start up when it does it runs fine.
I have replaced the PSU with no luck. Really hope someone can help me.
Thanks Old Dog

 

Solved, I think.
One of the googled suggestions was to remove/replace RAM. It worked! Have re-started several times with no problems! It's booting up better than it has been for the last couple of months

 

I am a bit surprised that worked. In the olden days, this process was done to scrape the corrosion off the contacts which was limited conduction through the contacts. Today, corrosion is not normally a problem - though improper handling is.

I wonder if, perhaps, one of your sticks was not fully seated in the slot, and you reseating them corrected that. At any rate, I am glad you got it sorted out and thanks for the follow-up.

Oh, and next time, don't wait months before you can't stand it any more!