Data hit a time warp.

So my work computer ( windows 7 ) gave me a warning about a failing hard drive. We have been running weekly backups on 2 different thumb drive, one for Quick Books and one for everything else. We got it running and backed everything up again then bought a new computer ( windows 10 ).
We got Quick Books up and running, restored the files and everything is fine. The other thumb drive was missing a lot of info so we plugged in the old computer, got it limping along and it was missing the same data ( and it thought it was year 2001 ) . I reset the date, no dice.
I noticed that even the files that still existed were old versions of those files. Basically all the data on the old computer and the thumb drive has been rolled back about 6 years. The QB thumb is fine and up to date. The rolled back files are mostly excel files but the backup of my thumb marks I did at the same time is gone too. I copied it to the thumb drive twice and the second time I was asked if I want to replace the one that is already there.
I can't think of any way this makes any sense. So any idea how to get the data back? Or at least not have it happen again?

 

First if this is an Office computer you should not be depending on thumb drives for backups. You should get an external hard drive or two and rotate backups between them. Probably two 500 GB Western Digital portable hard drives will work. One week back up both QB and Excel to drive 1 and the next week backup QB and Excel to drive 2. That way you are assured you always have at the least a 2 week old copy of everything on one drive.
The hard drives in an external hard drive is much better grade than the type used in thumb drives.

It sounds like the CMOS battery is close to dying too that why the date is wrong.
I'm not sure if you put in a new CMOS battery and reset the date to the current time if the files will appear. (I don't have any experience with this because we store our files, several copies of each, off the computer).

 

Thank you Plodr, I will get the external drives. I thought the thumb drives were good for back up but I guess not. I work in a restaurant so we don't have a lot of data and I do have hard copy of a lot of it. I've found a couple of posts online about this happening to other people but they only lost a day or two and no one could figure out why it was happening or how to fix it.
I am also reluctant to bring the old computer back up any more than I need to, it's failing very rapidly and I'm not sure if it will boot up even one more time. Any other ideas?

 

Well you could remove the hard drive and attach it by USB to a working computer after that computer has booted.
Then use Windows Explorer to look at what is on the hard drive and see if you can find any files newer than 6 years ago.

I use something similar to this

which has connectors for old and new style hard drives and both laptop size and desktop size connectors. It also has a power supply so the hard drive is not using it's own power to run.