Well, try to make sure you have the service packs for your operating system available to install right after.

For Windows XP, have the service pack 2 exe available. For Windows 2000, service pack 4.

you need to make your cd-rom bootable (in the BIOS) it prob already is but its worth checking

you should also delete the partition and then create a new one (max size)

then format to NTFS and choose the full (not the quick) option

BUT before you do any of this, make sure you have all your drivers for your hardware, and install discs for all your applications.

XP will ask you for activation, since you don't have broadband, you can skip this and do it later when you've set up your modem connection again, or do it over the phone on the automated service or with a Microsoft support person (numbers should be on-screen)

and make sure you've backed everything up, including your savegames and internet favourites.

Also make sure to block out the better part of your day to do this. I've had several reformat/ windows reinstalls fail at 95% and had to restart, with the process taking around 2-3 hours to complete each time.

Bad RAM or a bad hard drive. You could also have dodgy capacitors on your motherboard.

An install should not fail at 95% and force you to do it again to get it to go.

what HK says.