How do you fix the red screen of death on the ps3? Will the gilsky guide fix the ylod for good?

I have 2 ps3's. 1 has the yellow light of death. I am wondering if the way that gilksy fixes it will fix the ylod for good. The other has the red screen of death when you turn it on. I want to know if anyone knows how to fix it without spending a lot of money. I know that there are things like that can fix it but you need to pay. Has anyone paid and would tell me how to fix it? I have tried to replace the hard drive and the rsod still comes up. I have tried the safe mode and none of that worked. I have tried to format the hard drive and it still doesnt work.