First Hi and welcome to LQ.
The hp printer it will be best to use HPLIP driver that usually is listed with the later distro repositories or you can go here and download the driver.
http://hplipopensource.com/hplip-web/index.html
As for your dell you will have to check out a printer driver package called cups. Sane is the name of the scanner package.
Now for your display you will need to give your monitor make, model, and size. It would save someone some time if you could look up the vertical and horiz freq.
