Friends system shows that w32/nsag has infected wininet.dll of Win98. No anti-virus program I have tried, in safe mode, has been able to repair this file. Quarantining it makes it impossible to go on the net. Advice on rinstalling a clean file, or repairing this one would be much appreciated. Riva.

First, what version of Internet Explorer are you running, IE 5 or IE 6.To find out just do a search for the infected wininet.dll, right click it, click properties, click version tab then write it down and post it.

It would also help to see a Hijack This log if you can get on the net.You will most likely need to post a Hijack This log so that the files associated with the virus can be identified. You can download Hijack This at this link http://www.tomcoyote.org/hjt/ then place it into a folder of it's on, such as C:\HJT, so that back up copies can be made and not clutter your desktop or other folders and the backup copies of deleted items can be easily located if needed.

Once saved double click HijackThis.exe, and press "Scan". When the scan is finished, the "Scan" button will change into a "Save Log" button.
Press that, save the log, Ctrl-A to Select All, and copy its contents into the text editor.