I downloaded a file to my chromebook and it say it was designed for windows and not compatible for chrome os and to look in chrome web store for app so i can open file .so what do i do? please help

No file told,
no "downloader updater", app name or version told
let me guess you found and APP (run exe) on the web (www)
and want to load it on to Chrome OS?
what are you trying to do?
you said DVD there is no DVD drive on this thin PC. zero
so to read a DVD you must buy and externa USB l DVD reader.
the Chromebook runs Chrome OS, not windows !
so you run non windows apps.
"Chrome OS cannot natively run Windows executable's, as it is a Linux based system, and is pretty well locked down."
with some limited exceptions. (wine /crossover)
tell what end goal is, my wild wild guess is you bought a new external USB connected DVD drive and it does not work and forgot to ask seller if it runs on Chrome OS? oops.
oops I bet it does not run on Chrome, as most do not
but non driver maker or model told, so ask them first
your PC has no DVD drive ! so what do you have,
cheers and good luck.

Enable "Install apps from unknown sources" in settings. Go to the app vendor's website & if they have made the app available there (a downloadable apk), download and install.

First please realize that a Chromebook is not the same as a Windows laptop/desktop and your microscope will most likely never work on the Chromebook. This is because we are talking about two different operating systems, with the Chromebook having a very slim Google operating system, called Chrome OS, designed for mainly web browsing and using web based tools such as Google Drive.

You can try to find a driver for the microscope that you can download from the web straight onto the Chromebook. BUT remember, the driver HAS to be for the Chromebook. A Windows driver will not work!

If you need further help, I’m available over the phone at https://www.6ya.com/expert/thomas_e8f475a8655f7b4a

You will find the manual on this web page.

ASUS Chromebook C300 Support

Hello, This excerpt is straight from magicjack's website. Chromebook does not use any of those operating systems, it uses Chrome OS. This is not to say that it will remain that way but, this is the current state of their operating system support.

Your Question What operating systems does magicJack support? Category: All > Compatibility
Print Article ' Email Link Answer magicJack supports the most popular operating systems in the world:

• Microsoft Windows XP
• Microsoft Windows Vista
• Microsoft Windows 7
• Microsoft Windows 8
• Intel-Based Apple Mac

I dont know the chrome os is like. But if it has a settings button like you would on your S3 then my device then applications you can remove it there but if not then I cant help there but this is the link for google https://play.google.com/store/apps/details?id=jp.co.canon.bsd.ad.pixmaprint&hl=en

check here this explain well your problem
https://support.google.com/chromebook/answer/1700055?hl=en

You might be trying to get Paltalk from a source not compatible with Chromebooks. You can only use apps that are in the Chrome Webstore, which does offer Paltalk. Go here

https://chrome.google.com/webstore/search/paltalk
.

Try Firefox or Opera Mini, which is designed for Windows Mobile.