So you've had more than enough of reading about that bloody iPhone? We know the feeling! This week Troubleshooter dives back into the deep end of the personal computing pool, where we bump our head on a problematic printer belonging to Christine Kelty. Except that the problem turns out not to be the printer itself but Kelty's use of a refilled ink cartridge.

Kelty explained to Troubleshooter that she fitted to her Dell 922 all-in-one printer a cartridge "filled with commercially available ink, but the ink levels are registering low and the printer will not print or does so very faintly even though the cartridge is full. How do I reset the ink level? I have tried the ink company and Dell without success."

The issue of refilled ink cartridges is a vast and vexatious one. Most printer manufacturers insist that you use only their own cartridges rather than drop-in replacements made by other companies or even their own cartridges that have been refilled with ink.

Of course, the official cartridges cost a sight more - the profit on each new cartridge you buy through the years is how manufacturers offset the low retail price of the printer. It's a new spin on Gillette's classic and successful game plan of giving away the razors but selling the blades, with the further incentive that the use of a non-official cartridge can void the printer's warranty.

We took Kelty's case to Christian Young, Dell's product marketing manager for printers. Young says that the false alarm on the low ink level is due to the use of a refilled cartridge rather than a new one. "Once our Dell ink cartridge fill levels fall to a certain level, the user will be prompted to purchase new ink cartridges via the Dell Ink Management System. Refilling the existing ink cartridges will be of no avail as the printer will recognise the current ink cartridge as an empty cartridge with the ink level 'counter' a low-empty."

This is part of Dell's strategy to discourage the use of remanufactured and refilled cartridges, Young says, because "studies [by Consumer Report and PC World magazines] have shown that such cartridges have higher failure rates and significantly lower quality".

We're sure the legion of ink-refilling companies will disagree. However, readers should know this is a "gotcha" employed by many manufacturers to ensure that buyers will fit only proprietary shrink-wrapped ink cartridges.

Troubleshooter also had some follow-up email on the subject of laptops bought overseas but not necessarily covered by an international warranty. Among these was a rare "good news" piece, with reader Mark Cruickshank citing a happy experience with his Toshiba laptop. "My laptop purchased in Australia is being used in London by my daughter and on a recent visit I noticed that it was running hot. A phone call to Toshiba UK confirmed they had instant access to their international database and that the laptop was covered by their warranty.

"It was duly picked up, packed in tailor-made transport pack and returned fixed within five days as promised - all seamless and without any drama. I was very impressed!"

Can't get satisfaction from your ISP? New laptop on the fritz? Mobile phone provider driving you nuts? Tell us your problem and we'll try to help: email troubleshooter@smh.com.au.