HP845C blank ink print problems

I don't know why, but my black ink cartridge prints faded like it' s
running out of ink. But, I know it is not.
I have a dual boot system, primary partition WIN98SE, secondary
partition Mandrake Linux (10.1, I think). When I print using Linux, I
have no problems printing black ink on plain paper, text or otherwise.
In WIN98SE, however, it prints either not at all, or so faint
it's almost not there. I tried downloading the latest driver from the
HP url, and the program tells me that it can't find my USB port. I
e-mailed with HP tech support, and even had them email me a program to
positively uninstall my HP software and reboot still can't find USB
port! However, when I reinstall the old print driver software from my
CD, I have no problems finding the USB, and things work just fine.
I can't figure out how to reload WIN98SE, since it seems the
software can't cope with my dual boot machine, and I don't want to
reformat my hard drive just to take care of this prob.
As a workaround, if I go to advanced setup before printing when I
get the dialog box, and tell it to print out photo paper, and then
take the option to say I'm using high quality matte, my black ink
prints out just fine, but very slow. I've done about 100 letters and
envelopes this way, but I'd like to go back to normal and quicker
printing.