SAN FRANCISCO (Reuters) - A new e-mail virus that promises an eyeful to Internet users but instead cripples Microsoft Windows emerged Tuesday, although anti-virus software companies said they had come up with a cure by mid-afternoon.

This destructive worm appears as a forwarded e-mail with ''Naked Wife'' in the Subject line. Readers who click on the attached file, called ``Naked Wife.exe'', will not get a nude picture, but will instead see a short cartoon followed by a vulgar message, signed by ``BGK (Bill Gates (news - web sites) Killer).''

All the while, the virus is deleting key Windows and system files on the user's PC, rendering the computer unable to start up properly, according to Susan Orbuch, a spokeswoman for anti- virus software maker, Trend Micro Inc. (NasdaqNM:TMIC - news)

Similar to earlier worm-type viruses like Love Letter and Melissa, NakedWife can spread quickly by e-mailing itself to everyone in a user's Microsoft Outlook e-mail address book.

At least 25 corporations have been infected so far, according to McAfee, a division of security software maker, Network Associates Inc. (NasdaqNM:NETA - news)

Users who receive the e-mail should not click on the attachment and delete it immediately. The virus, written in the Visual Basic language, deletes files ending in .bmp, .com, .dll, .exe and .ini in the Windows and Windows Systems directories.