Ad 72415 burner

if you are referring to 7 Multi Touch Tablet . Look at the specs page https://ematic.us/shop/egm002.html#Tech-Specs
It does not support Bluetooth and cannot be added.
It is hardware component and cannot be added from playstore.

remove the knob, the center shaft is hollow, slide in a small blade screw driver to adjust the flame cheers

You're not "pushing" with 1x speed, that's the slowest speed at which a burner will burn at. You can change the write speed in the burning software settings.

According to the specs at Buffalo-Technology it sure is Window 7 compatible. You can check the specs out here: http://www.buffalo-technology.com/files/products/DVSM-PN58U2V%20-DVD%20MultiDrive%20DS%20EN.pdf

Here is a link to the specifications of your burner.

Look in the Technical Specs and under supported media format they have listed "dl".

If anything you may have a firmware update available. (you can check on this site for any available ones).

Hope this helps.

http://www.sonynec-optiarc.com/products/hhid_dvdrw/ad7200.html

optiarc ad-5170a is for dvd-rw only

Specs from Dell Website

According to the Specs it should be able to burn DL+R, but not DL-R. Nero Express should work if it's a recent version that supports your model. An updated Nero version will have more support for different models of burners, but another great free software that can do almost as much as, if not more, than Nero Express is CD Burner XP, which is freeware and can be downloaded directly from their website CDBurnerXP

are your disks supported by the burner , note the burners specs say it only supports a cr/-rw disk maqking any other unrecognisable to the burner to write to.

what is your cpu, ram, dvd drive specs. it may be as simple as either adding more ram or upgrading the cpu, or updating the driver for your dvd burner

Have a look at manual below
http://www.dacor.com/Dacor.Website/WorkArea/showcontent.aspx?id=1297

Or select from here
http://www.retrevo.com/s/Dacor+ERD30?rt=mi&p=http%3A%2F%2Fwww.dacor.com%2FCustomer-Care%2FManuals-And-Specs.aspx%3FTaxonomyId%3D509