Now I was really in. The screen cleared to be replaced by the same pale blue, this time without message and without horizon. It was tempting to stare at it, imagine being drawn down into its limitless expanse.

A new message appeared. It said: Installing temporary files. Do not remove the source. My hard disc signal light began flickering at great speed.

Sense and computer experience finally returned to me in force. With a feeling of mild panic I jerked forward in my seat and jabbed anxiously at the eject button on the card reader. The card popped out.

The screen instantly said: Replace source immediately. Registry files have been overwritten.

I sat and stared at the monitor, indecision sweeping through me. What would happen now, if I switched off or rebooted? Alternatively, what would the software do if I let it continue?

I had been using computers for years and profoundly respected the rule that one should never run unknown or unverified software. This time I had blithely ignored that. The risk of viral infection was real. But then – I had state of the art antivirus software installed, and that worked reliably every day, neutralizing threats and calmly reporting its mysterious effectiveness of transferring malware into quarantine, or permanent oblivion.

I was curious about the software contained in the card – the hotel was a responsibly run business, part of a large chain of hotels, and two or three weeks after my one-night stay I was still wondering about what mistakes I had inadvertently made with this card. Wondering, but not obsessively so.

On the whole, I judged it safer to reboot.

Then the program message changed again. It was an identical warning about registry files, but now the words were displayed in a larger typeface, bright red, flashing urgently. Replace source immediately.

I pushed the card back into the slot. Installation of whatever it was resumed.

Half an hour went by. Messages appeared at intervals, informing or reassuring me that unexplained actions had been successfully completed, that old and obsolete files had been safely removed. It did not say which ones they were.

A narrow green bar at the bottom of the monitor screen was crawling with glacial sloth from left to right. It had a percentage sign above it. It slowly reached 50 per cent.