Son accidently set all files to open with 7-zip

I don't think it's possible to have 7zip handle all file types... Regardless, you should be able to manage the associations in 7zip itself. I'm not sure if there is a reset button but you can press but if you can't get Windows to boot you have a bigger issue at hand. How long have you run Chkdsk? If it's running for an hour or so, that's pretty normal. The only way you are going to lose your data is if the drive is formatted, otherwise I wouldn't worry about it.

There are ways to retrieve your data by booting off of CD. I would try to boot a Windows CD and try a repair install. Chkdsk will do nothing to fix the problems with the registry. If you can't boot into windows either in safe mode or normal mode you will not be able to do a system restore but you can still retrieve your important files. What type of PC is it. It if is an HP or Dell or some other name brand it may have a way to do a non-destructive system recovery but that's a big maybe.

Just like gguerra mentioned, you shouldn't lose your data just by doing a recovery (repair install). If the files on your HDD is very important, I would go out and purchase a replacement HDD, and use the current HDD as a secondary (backup). It's the safest solution

It is a HP laptop with Vista Home Basic. I was just trying to think of an inexpensive way to keep from losing my data. I'm a single parent and don't have lots of money to spend. How much would a HDD cost?

You should be able to find one for under $100.
Since it's a laptop, you'll also need an external enclosure for around $50 to hook it up.

I guess we may be without a computer for awhile. Thank you both for your help.

You should be able to do a recovery without losing any info though.
My biggest concern is how this happened. It isn't exactly a 'one-click' procedure.

Buy yourself a cheap Flash Drive (Less than $10 for a 2 or 4GB). Use a Free tool such as this Paragon Rescue Kit, save your files to the flash drive. Then you are free to try anything else. A Repair Install, System Recovery, which should be built in to the HP Laptop usually by pressing F11 or something like that. It should tell you when you see the HP logo somewhere on the same screen. It may have a non-destructive restore (meaning it will not affect your files) or a full recovery. It doesnt really matter because you would have already backed up your files. Forget buying another hard drive. How are you going to do that on a laptop?. It is easy on a desktop but not on a laptop.

I'm not really sure what my son did concerning the 7-zip. He's 12 yrs. old and could probably explain it better than me. He tried to figure out a way to use Linux from a CD to get into the computer, but it didn't work. I have a flash drive and will try the Rescue Kit. That way, if recovery can't do a non-destructive restore, my files will be safe. Thank you all for your help.

Why don't you boot into Safe Mode and disable 7Zip? Take it off of Startup. Once done, boot into Normal Mode- ignore and close nag message after checking 'don't show this message again.' Stay in Selective Startup.

Control Panel> Folder Options> File types tab> change the 7zip on the file types it shouldn't be opening. For instance, for .doc, change to Word or Office. For PDF, change to Adobe or FoxIt- whichever you have.

Since 7zip is to open zipped files, the only file extension that need to be set for 7zip to open is .zip.

Somehow he went in to Folder Options, change a files extension to open with 7 zip, then checked 'apply to all file types'. Just undo his mischief!

1) If you have a large hard drive, it's not unusual for chkdsk to take a looong time to run. (Allow 30+ minutes for the display of % complete to change before assuming chkdsk is hanging)

2) Also see [post=766270]How to recover your folders/files when Windows won’t boot[/post]. You can try booting into Knoppix to get to your files.