Computer magazines offer advice on setting up dual booting systems, but very little about undoing the setup. My 120GB hard drive is partitioned (using Partition Magic) as follows: C: Windows 98 SE, D: Data, E: Temp, and F: Windows XP. All drives are FAT32 except drive F which is NTFS. Reading articles on the internet there appears to be conflicting information about how to remove the dual boot without upsetting the MBR and making the HDD unusable. Could you please outline a set of steps to remove the dual boot setup leaving Windows 98 SE intact on the C drive, with the other partitions empty? Also, can Windows 98 SE be reinstalled over the top of the existing installation, as there is a corrupted file in my Windows 98 SE installation which won’t allow installation of the correct driver for the PCI bus?

Before doing anything, I suggest that you backup any important information held on your hard drive as there is always a small chance that you are unable to boot your computer. Once you have completed the backup, there is a procedure we can use to overwrite the XP boot loader and make Windows 98 SE the bootable operating system. Firstly, you will need to create a Windows 98 boot disk. Go to the ‘Start’ menu > ‘Settings’ > ‘Control Panel’ and open ‘Add/Remove Programs’. Click the ‘Startup Disk’ tab and click the ‘Create Disk’ button. Once the startup disk has been created, we need to copy an extra file to the disk. Open Windows Explorer and navigate to C:WindowsSystem. Copy the file SYS.COM to the newly created boot disk. Restart your computer with the boot disk in the drive. If you are prompted to start your computer with or without CD-ROM support, select without support, since we don’t need to access the CD drive for this procedure. Your computer should start to a DOS prompt, looking like A:>. At the prompt, type the command ’sys c:’ (without the quotes). This will install the normal Windows 98 boot files on the C drive, making Windows 98 the bootable operating system. Remove the boot disk from the floppy drive and restart the computer. Windows 98 SE should now boot by default. Once Windows 98 has started, you should be able to safely delete the Windows XP files from the F: partition. If you wish to merge the D, E, and F partitions, then you should use Partition Magic for this task.

While it is possible to reinstall Windows 98 over itself, theoretically without losing any data, this may not be the best solution in your case. There is a utility included with Windows 98 called the System File Checker (SFC). This will scan your Windows 98 system for any corrupt or missing files and then extract a new copy of the affected file from your Windows 98 CD. Go to the ‘Start’ menu > ‘Run’ and type ’sfc’ (without the quotes) and click OK. In the window that appears, select ‘Scan for altered files’ and click the ‘Start’ button.