Few days ago,I bought a Dell 486 machine,model 433NP and it had Win98SE installed.

I decided to format the drive and install DOS7.1/Win311 on it.I hooked up its HDD to my P133 machine and installed DOS7.1/Win311.

I returned the HDD to 486 and it won't boot from it saying 'Invalid System Disk'.But,on P133 HDD booted normally.486 auto detects the drive,but it won't boot it.I can boot 486 only from floppy and then I can access the HDD and run apps from it.
I tried user define option in setup but the same thing happens-it won't boot.

HDD - Premier 504 MB,the BIOS detects it as 406 MB,it worked fine until I installed DOS7.1.
How can I get the drive to boot?

Thanks for help.

FYI MS-DOS7.10 never officially existed!

The problem you have is that the P133 and the 486 recognise your hard drive geometry differently.

Thanks for help.I think the only way to get it working is to hook a CD-ROM to 486 and install DOS from it using a floppy bootdisk w/CD-ROM support.

Walter,about MS-DOS 7.10 see this:
http://www.computing.net/windows31/...

Actually the versions of 7.10 from China Dos Union and ZDOS Russian are hacked and use Licensed Software Illegally.

The underlying MS-DOS susb-system from W95 original was equivelent to MS-DOS 7.01.

Windows 95 OSR2.xx/W98 was equivelent to MS-DOS7.10.

Windows ME was equivelent to MS-DOS 8.

Apart from MS-DOS 7 OEM Special Version, the last official licensed and legal standalone version of Microsoft's MS-DOS was Version 6.22.

Theoretically to use the underlying MS-DOS from Windows 95/98 one should hold a License for the versions of Windows, not to mention Windows 3.xx is also Licensed Software.

Why did you put the drive in another computer to install dos and windows?

What's the model # of the drive? You say the 'bios detects it as 406'. Was that done via an 'auto detect hard drive' in cmos/bios setup or are the C/H/S figures entered manually?

I put the HDD in another computer because of CD-ROM.486 can hardly work with CD-ROM.
It was done by auto detect option,but I also tried manually,it won't boot with that drive.

I attached a very old HDD I had with DOS and it boots well,despite the fact that I installed DOS on it on another PC.This one works well,but it's smaller - an IBM 170MB HDD.

Boot up with the bootdisk and type fdisk/mbr and enter at the prompt. Then type sys c: and enter. Then try rebooting again.

What is the C/H/S listed on the drive label?

>>>486 can hardly work with CD-ROM.<<<

Unless there's something horribly wrong with the machine (perhaps a toasted IDE controller--but then your HDD would never work), there's no reason a 486 shouldn't work with a CD-ROM. I've got a 386sx-16 with an internal CD-ROM (and only a 200MB HDD) which work perfectly together. I've even used one on a 286 with only 640K of RAM. Using it with DOS, you'd have to have a driver for it to work. Here's a good generic one:

ftp://ftp.mitsumi.com/pub/drivers/ide158.exe

I'd suspect Walter & DAVEINCAPS assessment of the drives' geometry being recognized differently in the two machines is correct (and Walter's also right about CDU's DOS7.1 being pretty much illegal)