Mobile PC won't start anymore...

Maybe it's an OS bug; you should check if your Windows hasn't gone haywire.

Hi, it seems like a hard drive issue.
If it's under warranty, bring it in..

Thank you for your answers.
As for returning it under warranty: after calling Acer, I understood that the warranty only covers hardware and not data recovery.
I was clearly told that if I returned my PC, they would change the hard drive and everything would be erased.
I’m going home on Tuesday (I’m currently on vacation) and I think I’ll connect my external CD drive to my PC and put the recovery CD in it and boot from there, then use a data recovery software to see what I can recover.
What do you think?
As for hiring a company to recover the data: it costs a lot, 100 euros to recover video and especially a lot of Word documents.

I've had my computer for a few months (since early March 2012), so it's still under warranty, and removing the hard drive will void my warranty, that's what Acer told me this morning.

Once I get back, I will try Hiren's Boot CD.

Otherwise, what can I do while I'm waiting to get back??? What can I attempt???

Are there any settings to adjust in the BIOS of my Acer Aspire One 722 (but I don't see which ones!)???

It works, I will come back after doing what Rhoeas advised me.
Thank you all for your help!

I don't know if this will be useful to you, but the reasoning is as follows:
the computer shut down because there must have been a short circuit or something (obscure reason)

following that, the PC tries to boot from the network through your network card (PXE) because in your BIOS, the boot order should be as follows:
- hard drive
- network card

there may also be a CD drive included, but that doesn't change anything since no bootable CD is inserted (I presume)
However, depending on the model of your laptop, it is possible that the hard drive has simply disconnected or short-circuited, hence the "hdd model name none" because it is not recognized as plugged in.

As you have a warranty in progress, I strongly advise against disassembling your computer; go through your store or call Acer's customer service so they can take your computer in for warranty.
At best, they will notice the problem; at worst, they will replace your hard drive, but you will lose your data.

If you have any other questions, feel free to ask; otherwise, you can mark your topic as resolved.

Thank you Julien for taking the time to help me.
Indeed, the bootable CD was created as soon as I received the PC and it is at my home, however I am on vacation until Tuesday.

I am in a huge panic because I have a ton of professional documents (Word/PDF/video) on the hard drive of my Acer Aspire One 722 that I really don't want to retype or ask those who sent them to me again or lose...
That's why I'm hesitating a lot, a lot to send my laptop to Acer's after-sales service, because I'm afraid they will change the hard drive and that everything will be lost...

Hello Julien
Here's what I'm going to do: tomorrow I'm going home and there, with the backup CDs I created when I bought the PC, I'm going to try to boot from them and then I'll use the Hiren's Boot CD software.
If this software doesn't work, then I will use a data recovery software like Recuva or SoftPerfect File Recovery.
If nothing works, on Wednesday I'll send the PC to Acer's customer service and I'll get the hard drive back if they've replaced it.
Once I receive the defective hard drive, I will send it to a company that does data recovery for individuals...

Hello Julien.
I will do as you said, booting first from the Hiren's CD and then from the backup CD...
I almost forgot, my system on my Acer Aspire One 722 was Windows 7 Home Edition and not Windows XP.
I will come back here to say whether it worked or not.
One more thing, is there a tutorial in French for using the Hiren's CD?

Thank you Julien for the clarifications and for the tutorial that I just downloaded.

Hello everyone, and thank you for your help.
Here are the latest news: I tried the Hiren software, then I tried my backup CDs, but nothing worked, so my laptop went to Acer's repair service this morning.
Do you think it could be a virus that is damaging the zero zone of the hard drive?
It seems plausible to me, although all my emails are scanned by the antivirus and suspicious emails go straight to the trash...

This happened to me when I exited an Acer game that was already installed on the computer in the free version, and I was playing that free version.

The hard drive of the laptop burned out and Acer's customer service didn't give me any more details.
The hard drive has been changed, but to recover the old burned hard drive, I had to pay 100€, thanks Acer!
In short, my experience with ACER is not great and I will soon be changing laptops and this time I'm going to invest the necessary amount to get something top-notch!
Conclusion: it’s better to pay for a quality laptop rather than buy a very mid-range one (although I should note that I had a Samsung NC 10 for 2 years and it gave me no issues!)