Help me fix my PS3's freezing issues, please?

A couple of months ago my PS3 started freezing and there would be a bunch of green and blue lines shooting across the TV screen, at the time I'd done some research and found another question on this site that said I would have to apply thermal paste to the GPU; so I did.

It didn't work, so I gave up hope and decided to wait until I had enough money to get it professionally repaired or buy a new one entirely.

However, since it's been a couple of months now, I'm getting a little impatient and was wondering if anybody on this site had a little more input.

A couple of videos on youtube from people who'd had similar issues claimed that I needed to reflow the GPU, I don't paricularly feel like breaking my PS3 for good because of my abysmal soldering skills, so would anybody be able to confirm that a reflow is necessary?

Also, for a base of reference: http://www.youtube.com/watch?v=uFgeicAFA...

Skip to about :51 to see what I mean.