I tried fixing my laptop but it won't power up so cost wise would it be better getting it repaired or buying a new one?

Always a gamble, some repairs will see the laptop last years, other laptops might fail again.

If its just a power connector problem or similar it is probably worth doing, if its less than 3 years old and a premium make its probably worth doing but outside of those constraints its approaching gambling territory and probably no right or wrong answer.

I've had a Compaq which I repaired twice in over 10 years, I've had a Dell that lasted over 8 years without any problems, but I've had numerous other makes and Dells that just limped from repair to repair.

I tend to buy second-hand from a refurbisher that provides a warranty (and assume it needs a new battery) but my current one was a used private item which I'm very pleased with - I just got lucky.

So if i were to get it repaired how much roughly would I need to spend?

Unknown
Until the Source of the problem is found.
You need to find somewhere that will look for free.
But if they start to say, we can replace this first and then that, it means they don't have a clue.

If you going to pay good money they should have the equipment to test for a failed component.

You've not said the age of the laptop or the spec.
Which would have a baring on the decision.

I've had for 6 or 7 years it's a Hp dv4-1435dx.

When you say it won't power up, do you mean there is no sign of life at all or it appears to switch on but won't boot into windows?

2.1Ghz dual core processor in a laptop is slightly on the slow side for today's standards, within 2 years it probably will be really dragging its feet. It may already has slight problems watching high definition Youtubes in full screen mode and may be slow on sites with active adverts.

If I thought I would be buying a new laptop in the next couple of years, I would probably bring that forward instead of repairing it. My opinion, slightly biased because I don't want to give too much of a wooly answer, it is close to the borderline, I'd be interested if others agree or disagree.

Probably the start of more problems to come.

Put your money towards a New or Refurbished Laptop.

Your probably running XP which is no longer a supported operating system anyway. The reasons to stay with a broken 7yr old laptop is stacked against you. in my opinion.

Laptop won't turn on there is no sign of life at all. No power I tried changing the power jack but there isn't any power going into it. Charger seems fine. When I bought it, it came with Windows 7. Everything was running smoothly even watching it in HD youtube videos.

So If it's not worth repairing. What can I do to transfer some files from that hard disc onto another computer?

There is a little shop on poulton road that solders power jacks so if you think it is that buy one for a couple of quid and he will solder it for you for about a tenner if your lucky it will be one with wires so you can just UN plug it and plug a new one In

Take it to Akita Consoles at 387 Poulton road and ask Roy to look at it for you. I don't think he charges for an estimate. Very reasonable rates.
Ring him on 07725721413
www.akitaconsoles.com

That's the one I was trying to think of very good service and nice people