The extra drives could be virtual drives that some burning programs install when they are installed, you need to check if this is the case.
If they are virtual drives, the easiest way to get rid of them is to uninstall the programs that put them there, on reinstalling them select for a virtual drive not to be installed.
To do a fresh install, go into the BIOS and in the Advanced section Select for "First Boot Device" CDROM.
On boot up it will say "Press any key to boot from CDROM" so press a key.
Then follow the various screens to select to format C drive, when this is done XP will be installed.
When the comp restarts as it does a time or two during the install it will say "Press any key to boot from CDROM" again, DO NOT PRESS ANY KEY or the install will start over again, leave it and after a few seconds it will resume the install.
Once XP is installed, go back into the BIOS and select as "First Boot Device" FLOPPY.
If you plan to use the onboard LAN, take out the network card befor you start the install of XP.