Firewire for Inspiron 3647

You should be able to use something like this

www.newegg.com/.../Product.aspx

... that said, if your camera is old enough to require firewire and you don't have  a stock of old tapes, etc. to convert (such as 8 mm, VHS-C or mini-DV), you may be better off upgrading your camera to a USB version.  At minimum, if the camera requires software, be sure it is compatible with Windows 10 - - again, an older camcorder may not be.

I don't plan on buying a new camera.

I have a Canon ZR800 NTSC camera that using mini DV.

Do you think that will work with my computer and that new firewire port you recommended?

The issue with windows 7 and 8 and 10 is Texas Instruments Chipset and the fact that movie maker is removed from windows.  Both Apple and Microsoft have discontinued support for firewire.

https://blogs.msdn.microsoft.com/usbcoreblog/2014/09/10/announcing-the-availability-of-a-standalone-legacy-1394-ohci-firewire-package/

http://www.motu.com/techsupport/technotes/using-the-legacy-firewire-driver-in-windows-7

FireWire port-based device does not work correctly in Windows 8.1 or Windows 8

https://support.microsoft.com/en-us/help/2970191/

I would recommend this Specific card
https://www.amazon.com/SIIG-FireWire-2-Port-PCIe-NN-E20012-S2/dp/B000G6U8VY

Unfortunately Windows Live Essentials 2012 is no longer available.

https://www.pinnaclesys.com/en/products/studio/

Which firewire do you suggest I buy and install in my Inspiron 3647 that is running windows 10?

Before buying anything, be sure your Canon software will run under Windows 10 -- it's required to access data over firewire, and the camcorder in question is a decade old - it was current in 2007.  It may well be Canon doesn't support it under Windows 10.

If it is possible to use the Canon imaging software under Windows 10, then go with a card that has Windows 10 drivers.  Not all will - as noted in the other reply, neither Microsoft nor Apple supports firewire any longer.

This issue occurs because the legacy 1394 bus drivers (1394bus.sys and Ochi1394.sys) are removed in Windows 8.1 or Windows 8 and 10 as well as directx 9 10 11 drivers.

Windows 10 is directx 12.

This is also why windows movie maker was removed in January

never to be downloaded again EVER.

https://support.microsoft.com/en-us/help/13785/essentials-2012-release-notes