red screen saying serious error has accurred

The red screen, is actually a hard firewall, that literally locks down the unit. One way you can fix this is by replacing the hard drive inside your PS3 with another formatted hard drive while backing up your PS3 hard drive into your computer/laptop.

I answered this in another post and it won't let me post the same advice.

Turn off power at the back then back on. Hold down power button near red light, fans will rush then it will shut down again to red light. Hold down power again until two beeps are heard. COnnect controller via USB cable and press PS button. Choose option 3 File System Restore, let it do it's thing and it should work. Mine red screened again but repeating the above fixed it when I chose 1080i not 1080p although I don't think that's the cause. Mine was fine for years until I joined the PSN last week.