Sorry, Comrade General, I somehow missed your replies...
Let's try a repair installation. You will need 1 NEW floppy diskette and your Win98 installation cd for this.
Download this Win98SE
startup disk and save the file to your desktop. Double click the downloaded file and, when prompted by the application, insert the floppy diskette into the floppy drive. This will create a bootdisk.
Start the problem machine with the startup disk in the drive...it should boot to the floppy. When you see the options screen, select the option to "Start with cd-rom support". It will load cd-rom drivers and finish loading to a command prompt (A:\).
At the A:\ prompt, type e: and press "Enter". The command prompt should change to E:\.
At the E:\ prompt, type setup.exe and press "Enter". This should start the installer.
Let windows install over itself and see if it will boot properly once this completes. This procedure will not effect your data, but will replace the system files, reinstall devices, and tidy up the registry.