I assume you Shut Down your computer because you don't have it connected to an adequate power surge/spike protection device.
If you really want to protect your computer in that situation, that isn't enough - you must unplug the computer, and unplug any other device that is connected to the computer that is not protected by such a device - anything AC powered, and unplug cable or phone connections. If this is the computer your specs are for, it is new enough that it probably has an ATX power supply and an ATX mboard. If you have both of those, ATX mboards are always powered in some places, even when Windows is Shut Down, or in Standby or Hibernate modes.
If ACPI is enabled in your bios, you probably don't normally see the "
It's now safe to turn off your computer " message at all.
"AVG shows Partition Table (MBR)Reading error and Boot sector of disk Reading error. "
It sounds like your hard drive, or at least some data on it, has been damaged by a surge or spike. I know of no way spyware or other malware can cause the read problems AVG found.
"However it boots into safe mode with no problems"
Safe mode loads far fewer things than a normal boot does - if the things Safe mode loads are not damaged, the computer will boot Safe mode successfully.
If the info in Brim's reference doesn't help, you are probably going to have to try one or more of several things.
Restoring a previous registry won't help if critical files needed for a normal boot are damaged or missing.
Test your hard drive to determine whether it is just some data that is damaged, or the hard drive itself is damaged.
Go to the web site of the manufacturer of the hard drive on another computer and download a free diagnostic utility, execute the download to create a diagnostic floppy or floppies, boot the problem computer with the bootable floppy, and test your hard drive. There are usually two non-destructive tests - a quick and a longer one - it should pass both. If it has problems only with the data organization on the drive and there is nothing else wrong, that's also a pass because there's nothing physically or logically wrong with the hard drive, but there are problems with your Windows installation.
If it passes the diagnostics, you will then know the problem is caused by damage to data and/or damage to a file or files in your Windows installation.
If it doesn't pass the diagnostics, you will have to connect the problem drive as a slave or a secondary master and salvage what data you want to save off of it onto another hard drive.
.....
If it passes the diagnostics, you need to try repairing your Windows installation so that the existing data on your Windows partition is preserved, rather than installing Windows from scratch.
Try running a 98SE Setup "overtop" your existing Windows installation.
This will not harm your existing Windows installation, but it can only fix things Windows detects as wrong, and/or replace corrupted or missing Windows files that are on your original 98SE CD. If running it doesn't cure enough of your problems and/or the problems are caused by damage to data or files not on the original Windows CD, you will probably have to make a clean install of Windows from scratch.
Insert a Win 98SE cd in a cd drive.
Boot the computer with a 98SE Startup Disk floppy made in Windows - if you don't have one you can make one on another computer with 98SE (Add/Remove Programs, Startup Disk tab), or download the contents of a 98SE Startup Disk from the web.
Allow the Startup disk to load support for the CD drive(s) (which is the default), and after everything has loaded type: setup (enter) at the prompt.
Install to the SAME directory Windows is presently in - usually that's C:\Windows - you MUST install to the same directory in order to preserve all of your existing Windows partition installation data.