Only after 5 reboots floppy-boot starts

Turning on the pc it only will boot after 5 cold reboots via diskette
A:-drive.

This started to be so when starting my other pc with xp on it out of
sleeptime. The whole network between the two pc was down and I had to
reconnect the two pc's again.
But I didn't succeed to normally let start the other pc with win98se on it.
Even so after scanning several times the harddisk
1. scanning wasn't possible anymore (stopped half way)
2. later on the booting of the A:drive only started booting after turning on
the pc 5 times on a row. The sequence of booting in bios-setup is: diskette,
IDE-0, CDROM. Starting windows in Save Mode also only succeeded after
several reboots.
When it was sometimes possible to start in Normal Mode the Desktop looked
like that of Save Mode, so it lookes like a resolution question of the
videocard. After a short period of time the system hanged very quickly.
Another time the booting up hanged with an error message that something
there was no extended memory driver installed. So too many different things
to mention. After scanning the harddisk with my anti-virussoftware (Norman)
in the beginning I found one 32-worm virus which I put in quarantain. Could
it be possible that I still find the results of that.

Because I still cannot start my pc normally I also cannot reinstall win98se
because of the hanging. The OEMsetup.exe file starts with scanning which
hangs everytime. When startin the setup.exe my whole harddisk will be
overwritten with a new install.

Can anyone can imagine that there still is a solution without completely
reinstall my harddisk with win98se?
NB:
1. Also after norton scanning which completes the scanning I still have this
problem.
2. I already backupped my data toanther harddisk.

Thanks,
Rob