To fix the PS3 flashing red light you basically either send it to Sony or repair it yourself.
Sending your PS3 to Sony
The benefit of sending your PS3 to Sony is that a trained and experienced technician will fix the PS3 flashing red light.
However it'll cost you $150 (unless your PS3 is under warranty). That's half the value of a new PS3! Also it can take up to 6 weeks to get your PS3 back, and when you do get it back you'll find that your HDD memory would have been erased (Yes! Sony wipes the hard drive).
Caution-If you open your PS3 case, you will void the warranty
Fixing it yourself
Firstly if you are even going to attempt to fix it yourself, you need a good PS3 repair guide. When you look for a good repair guide make sure it offers:
safe repair methods
step by step instructions
lots of pictures and maybe even some videos so that you better understand what you have to do
some sort of support such as a members area or email support so that you can ask for help if you get stuck
allows you to do repairs using simple household items
some sort of guarantee so that if it doesn't work you can get your money back
The benefits of using a good PS3 repair guide to fix the PS3 flashing red light are:
These guides usually cost less than half the price of sending your PS3 to Sony
Many of them offer 1 hour fixes
Some of them deal with a variety of problems that your PS3 can have. So if you fix the PS3 flashing red light and your PS3 unfortunately has another problem later in you may be able to fix that one too using the guide. Compare this to sending your PS3 to Sony multiple times paying $150 each time!
The drawback to using a repair guide:
You have to do the repair yourself...although that's not really a disadvantage if you are interested in electronics and want to see the insides of a PS3.
When I was surfing the net I found this good repair guide.Check it out for yourself keeping in mind the criteria above.