Hi, I'm coming to ask your help. I just did a scan with NOD32 (2.50.19) on my W98SE machine. I got this warning: ===== Scanning Log NOD32 version 1.1135 (20050609) Checking CRC of NOD32.EXE: Status OK Operating memory is OK. MBR sector of the 1. physical disk contains probably unknown TSR.BOOT virus . Date: 9.6.2005 Time: 23:01:06 Scanned disks, folders and files: C:; D:; E:; F:; G: C:\WINDOWS\WIN386.SWP - error opening (File locked)  Number of scanned files: 82135 Number of threats found: 0 Time of completion: 23:14:59 Total scanning time: 833 sec (00:13:53) Notes:  File cannot be opened. It may be in use by another application or operating system. ===== I am wondering about that "probably unknown TSR.BOOT virus" in my MBR. What has happened: Since quite some time I cannot use Acronis TrueImage anymore. Well, I can make a backup image from within Windows (not from bootable floppies), but cannot restore anymore. Desperate as I was, I tried (probably not very wise; I don't know) a tool which is mentioned in a sticky thread at the Acronis forum: PLEASE READ BEFORE YOU POST I am talking about a tool to fix your MBR. === Quotes from that thread === Sometimes you need to fix Master Boot Record on your hard drive. We have two special utilities for this purpose. 1. Using floppy drive. Please insert a diskette into the floppy drive and run the file available by the link below: http://www.acronis.com/files/support/mbrautowrite_en.exe Once the floppy is written, boot the computer from it and confirm that you want to fix the master boot record. You do NOT need to copy this file to diskette. Just launch it from hard disk (or any media) with the diskette inserted. === end quotes === Well, I am not saying that this has necessarily caused that warning from NOD32, but at the other hand my guess at the moment is that it is the cause. Some of you know perhaps that I use the file-integrity-checker ADinf32 Pro (see here ). Well ADinf32 gave me a warning, after I did use that MBR-fix tool, about a change in my MBR; see screenshot. For the moment I have NOD32 not let to try to fix that possible virus. Any help would be greatly appreciated ! Thanks in advance, Jan.