Need help installing Windows 98SE on a PC with formatted HDD


Nov 19, 2008
I own a Compaq Presario 5310US... it came from the factory with XP but I got a virus and the HDD needed to be re-formatted....I cant re-install XP cuz I dont have a I want to install 98SE since I have the disk and a key for it....when I start the PC it says invalid system disk...replace the disc and press any key to continue...and when I put in the 98 SE disk and press a key it goes into the Windows 98 SE setup disk menu and asks me to press 1 to boot from hard drive, and 2 to boot from I press 2.....or press down and enter....whichever....then it says: I/O error, replace the disk and press any key to continue.....what does I/O error mean, and how do I fix it so I can have a working PC.....thank you for your help^^


Nov 21, 2008
I'm guessing the hard drive is formatted in NTFS and not FAT32. Win98 can't read NTFS format. You may need to get a disk that can read the disk and allow you to reformat. Try

Do you really want to go back to 98?
Wouldn't the $100 for an XP disk make more sense in the long run?
If it came from the factory with Windows XP, then you have a Windows XP product key sticker somewhere on the case... unless you've removed it. You can order a factory restore CD from HP / Compaq for 10 - 20 dollars... that would be a much better idea than installing 98. If you can't be bothered to order the factory restore CDs, then you can borrow someone else's XP CD and use the sticker on your case to reinstall XP.
Or if you have a local computer shop take the computer with the XP license on it to them, show it to them and ask for them to burn you an installation CD for the OP/SYS on the sticker.

If you're lucky most will do it for you and just charge for the burning media about 5 bucks, the CD is useless without the product key, and you have a legal right to reinstall the operating system, as long as you have the license.
maybe your copy of windows 98 is not bootable. but more than likely it is because your HDD is NTFS. what you will have to do first is make a windows 98 boot disk (you will have to get a floppy disk or a blank cd) then once booted you can use a utility called FDISK to reformat the drive. it escapes me right now but does anyone remember the FDISK switch to replace the MBR?
Uh - "fdisk /mbr". But why the necessity to replace the MBR? Use fdisk in interactive mode to delete the partition - there shouldn't be any need to touch the MBR.

But I definitely wouldn't install 98 - it may not even run on this PC (it won't run on many modern PCs), and it's so much in the Stone Age compared to XP that you really don't want to be running it.
yea. i forgot. the only reason you would need to replace the MBR is if a newer version of windows was onstalled on the PC and your trying to downgrade to windows 98. but its always a good reason to avoid problems when installing


Dec 31, 2008
I fear I have to agree with Zoron this time.

With its initial hardware, the Presario 5310US would be more responsive with Me or 98, but you'd have zero security on the Web, as good firewalls have abandoned 95-98-98se-Me. And many more applications don't run on 98. Not all drivers for Usb2 on W98-98se work properly. So just borrow and copy an Xp Cd.

If your sticker is for Xp Oem, you need an Oem Cd. If it's the Home edition, you need a Home Cd. But licences are common to all languages.

Sorry for this after the fact brain fart, but some older machines actually had the OP/SYS restore partitioned on the HDD itself in a special FAT32 partition, I believe you had to press F11 or someting like that to access its features, I just ran into one of those sporting XP Home OEM on a HP machine.

Unless you LLF the HDD you don't format that partition when you do a format of the C:\ drive.

It was listed as the B:\ drive in the CMOS setup boot manager on that particular machine.

Check to see if you have that?

You may be lucky?

average joe

Jan 24, 2009
Are you sure your Windows 98 CD is bootable. Download a windows 98 boot floppy from put it in the floppy drive and boot it with CD Rom suport. It should also conatin Fdisk which can format hard drives. Delete the partitions and make an new one thats inder 2 gigs and set it to active active. Windows 98 Second Edition supports fat 32 but the whole install will be around 210 mb the maximum swap file size is 256 megs so 1.5 gig would be plenty. Really large hard drives freak W98 out and it wont install. Once running it can handle up to a 127 gig hard drive. After fdisk finishes reboot with the boot floppy and run setup. Your golden.

If your hard drive is a SATA drive give up. There never will be a SATA driver for Windows 98.