Actually, all of your questions were ansered very simply almost immediately but then you continued to confuse members with more nonsenical questions(and statements?).

The earliest thread, I told you immediately that any good quality 450W unit is more than enough for your system with a 970. You stated in that first thread that you have an Asus mobo, not Biostar. In the 3rd thread, r00t explained to you(very simply FYi) that yes, your motherboard will support a GTX 970. You were also told that the motherboard makes almost no difference, you're going to have a hard time finding a board that won't support a GPU.

"but why ? i will have to a get a new one anyway mine is currently a 500w and it needs to be higher."
This is what I'm talking about when I mention nonsensical questions and stupid statements that make no sense. Your PSU does not need to be "higher". A good quality 450W unit is enough for a 970, it's the quality of your PSU that matters. A bad PSU puts the entirety of your system at risk.

You've got a prebuilt computer, most prebuilts come with cheap PSU's so it maybe time for an upgrade.

You also said you have a budget of £150. That's not enough for a GTX 970 so I'm assuming that's for other upgrades, but you never mentioned what it was for. We can only help when we have enough information to do so. You asked questions before and got valid responses. Fact is, you've been answered about PSU, motherboard etc already and had help.