The end user has been left feeling the wrath of a virus he or she may not even had a clue about. Said to have been released as a protest against the Chernobyl disaster in Ukraine 13 years ago, CIH has ravaged Windows 95 and Windows 98 systems. Or simply, anything which a home computer user may have painstakingly and lovingly stored in the machine: documents, files, graphs, work-related data, letters, pictures, even doodling.

The virus is also estimated to have hit at least 500 companies - including National Stock Exchange, Videsh Sanchar Nigam Limited (VSNL), the railways, L&T, Cox & Kings and Lintas. At least 10,000 desktop computers were infected throughout the country.

But professionals areincreasingly rigging up PCs in their homes, and if they were not logged on to the Internet, they missed the signposts signalling a virus alert. Thus, on April 26, those who booted their machines stumbled on to the worst case scenario: the machine either displayed blank screens or messages that spoke of a `fatal error' before the virus got down to work.

When Sabia Viegas, a lecturer with K C College, switched on her machine on Tuesday, she saw a message warning her that ``all matter would be wiped out'. Ignoring it, she `entered', only to see ``something like a lunar eclipse on the screen. Then, the cursor got luminous and started orbitting. After that, the screen just went blank,'' she recalls.

Viegas had almost 1,000 pages of her PHd thesis stored in her machine, and some intuition on April 25 warned her to store the matter in another floppie. Thus, she lost just a chapter of her thesis, which itself amounted to at least 100 pages and five months of work. ``I count my blessings as I could have lost muchmore,'' she observed.

``What has happened is that the virus has partitioned the hard disk,'' explained Sailesh Kamat of Ascent Computers. This means that the information stored in the computer has been completely deleted. And software engineers add that there is no way to retrieve the information lost. The only thing that can be done now is to reload the programme and start afresh. For the professional whose workplace is his or her home, for academics, students, accountants, this loss is uncomputable.

``Computers are becoming an inevitable mechanism,'' wryly remarked Viegas. ``Once you get dependent on the computer, your intellectual faculties get differently positioned, and you tend to get laidback and leave everything to the machine.''

Something several computers users have learned the hard way. Media professional Sara Kapoor (name changed) switched on her home computer at 8.15 am to watch a blue screen and a message that declared that the machine had a fatal error. The screen stayed blank despiterebooting, adds Kapoor, and predictably, precious information has vanished forever.

Already, there are computer outlets in the city which claim that they can retrieve the data, for a hefty price, of course. But software professionals cautioned against harbouring any hopes that what Chernobyl wiped out, could be retrieved.