i feel hp quite good providing some automatic installer for linux. but for slackware i find quite uneasy to install it. once it installed, there’s a trouble like the ink won’t print out. while in windows it worked well.
run #hp-check -t
to find out the lack of your slackware.
then download the necessary dependencies not found
2. cups-devel (any in slacks?)
10. python-devel (any in slackware?)
12. python2.2 or greater
after all check u can add the printer via cups or regular setting – printer