Long story short I've owned a laptop since September 2007 which came with a 1 year warranty from Toshiba and an extra 1 year from John Lewis.

In that time it was sent back twice for the same problem, and came back both times unfixed. Most recently in July this year. So I decided that I could live with the problem. (It had a variety of charging issues – one of which was that if you were running it without a battery inserted and restarted, it would fail to restart until you either removed and replaced the charger or inserted the battery)

This morning I was running it without a battery inserted and ran windows update. Which then went to restart, except it didn't boot up afterwards. Now it won't boot at all no matter what I do. No sign of life whatsoever when pressing the power button.

It seems linked to the various problems of before so now I wish I'd pursued a warranty repair at the time.

Normally I'd say that since it's out of warranty I'll either face a hefty bill or not be able to get it fixed at all.
But given that it has been a (twice) reported issue, and returned by them within the last 6 months do I have any leg to stand on?

Hmm. I'd reckon that by not pursuing it last time you've accepted it as OK. Keen to see what everyone else thinks tho.

Why would you run without the battery?

Running it without a battery tends to make the battery last longer.

You are not meant to run without a battery, I believe it helps regulate the mains supply. The way to maintain the battery life is to let the laptop run on the battery every now and then until it prompts you to recharge.

I think you might have trouble getting anything out of them since as far as they are concerned, the lappy was repaired.

Mine is just over 12months old and has just started giving me messages on boot up that my power supply is under-rated and not giving 'optimal performance' 🙁 It also has fits occasionally, constantly playing the connect/disconnect sound as if I'm unplugging a USB device.

Running it without a battery tends to make the battery last longer.

Running it with a fully charged battery should cause no problems at all to battery life, it's only actually cycliing the batter that damages it. As above, running the laptop without the battery may indeed remove some protection from the PSU circuitry, depending on how it'd designed. Many chargers and SMPSs don't like running without the known load of a battery.

I run it off battery power every day. It's just that when I'm sitting in one place and the battery is fully charged I'll remove it to prevent overusing it unnecessarily.

the battery is fully charged I'll remove it to prevent overusing it unnecessarily.

Once the battery is charged you're not using it, the charger keeps it happily topped up with next to no power and the computer runs happily off mains.

I agree, that should work in theory, but this particular laptop has charging issues and I just don't trust that it's doing that!
I'm already on my second battery – at the last repair they replaced they original as they said it had deteriorated far more than they would expect in the time period.

Then you've risked your PSU circuitry rather than your battery. Not a good move IMO. Laptop batteries don't last that long IME, because they are constantly deep cycled. WRT to your original warranty, nope, I think you've unfortunately accepted it as OK by not complaining last time. They might be really kind and offer to reduce the costs of repairs due to your history of problems, but they may consider your battery-jiggery-pokery to be just cause to refuse.

Running it with a fully charged battery should cause no problems at all to battery life, it's only actually cycliing the batter that damages it

Yeh there is a limit to the recharge cycles but you also need to consider memory effect on the battery depending on type. Its like those Ni-Cads, need to discharge fully before recharging otherwise you lose capacity.

Hmmm doesn't sound too good. There is very little warning that that could be the case though, and one of the checks that Toshiba asked me to do the first time I returned it was to see if it ran without the battery.

If there is now an issue with the PSU circuitry, is that something that could be repaired?

If you have no luck with the warranty, you best option might be to try either a new battery via ebay, or try and find the same model laptop as yours but with a knackered screen or something, then you can make one good laptop out of two knackered ones.

Or just pay for them to repair it, might not be as bad as you think.

It just turned back on!!

Pretty relieved at that. Maybe I'll rethink my battery saving strategy. I can easily buy a replacement battery if necessary. Not so easily a new PSU.

The problem with the, err problem, it had was that it was intermittent. With no obvious pattern.
In addition to the running off mains problem, often if you put it to sleep then woke it up again windows would tell you the ac power was plugged in yet the battery % would actually decrease until it reached 0 and cut out with no warning.

On the last day of the warranty I was going to take it into John Lewis but couldn't get it to replicate the symptoms so figured there'd be little point in doing so if I couldn't even show them what the problem was.

have you tried it on just the battery?

could be the power brick thats buggered rather than the power supply circuity in the laptop itself

Yeh there is a limit to the recharge cycles but you also need to consider memory effect on the battery depending on type. Its like those Ni-Cads, need to discharge fully before recharging otherwise you lose capacity.

Cell memory is a myth, they just degrade in capacity as anything does, fully discharging does nothing but create the same "wear" as semi-discharging and recharging twice.

Glad it's alive again but really I'd have asked for a replacement as they hadn't fixed the fault first time.

It started on just the battery, so I haven't actually tried plugging it in yet. The charger definitely works fine though, as I already tested it on another laptop.

Glad it's alive again but really I'd have asked for a replacement as they hadn't fixed the fault first time.

I now wish I did too, but certainly all the symptoms to date are very easy to live with. You just sometimes have to remove the ac adaptor and plug it straight back in again after a restart/waking up.

I didn't really think far ahead to consider that other faults could arise from what I suspected was a faulty PSU.

Well no harm done, easy to criticise with hindsight eh!