Yeah, but the problem with ms-fdisk is not the fact that it can't see the Linux partitions, but it only copies the previous mbr back onto the mbr. Even if you re-type and re-format your Linux partitions as fat32, you'll still be presented with the LI prompt (or whatever the Grub one is).
[begin rambling] A while ago (about 18months) I tried installing QNX. It didn't work, so I tried to install it again. It still didn't work. Then I found that the current MBR was that of the QNX boot-loader, and so was the previous MBR, so doing an fdisk /mbr would not help me at all. At the time I hadn't heard of XOSL, so the only way I could revert back to a clean Windows only MBR (this is just before I gave Linux a try, mind) was to format the harddisk and re-install Windows. Now, since I intend to keep at least Mandy on my current system, I'm quite happy having LiLo as the boot loader, but I keep XOSL on my Windows partition so that should Lilo go cockeyed (through my own fiddling) I still have a decent boot loader that I can install from a dos-boot-disk, and boot to Windows with. [/end rambling]
Tarak, this may sound long-winded, but give this a go:
Boot to Windows. Make a boot floppy. (If you already have one, you can skip it).
Boot to Linux. Go to the command prompt (the thing that looks like DOS) and run
cfdisk /dev/hda. Select the Linux partitions and make them fat32. Now, Linux is likely to go tits up now, so boot from the Windows boot disk you just made. Type
fdisk /mbr. Reboot the machine. If all has gone well, you will be able to boot straight into Windows, upon which you will be presented with another drive under My Computer. Format it. Hopefully this will have everything sorted, but it might be more difficult than this.
I would strongly advise that you download
XOSL now, and have it ready on your C drive. Should everything go horribly wrong, you can do the following:
Boot from the Windows boot disk. Go to the directory into which you installed XOSL (I have mine in C:\XOSL for ease) and run it. You will be presented with a set of options, I would advise that you install XOSL into the MBR rather than giving it its own partition (that would just complicate matters even further). Reboot. You will probably then be able to set up which OSes are on your harddisk - since you will only have Windows, it shouldn't be too bad. Once you've set it up, reboot and cross your fingers!