sorry man, but I don´t think there´s an easier method if you want to keep the data on the HDD. you could do a normal install, but of course the data will be lost then. you can try to repair the installation, boot from the XP CD and chose "repair" instead of new installation when you´re asked for it, but this would take much longer than the first method.
your problem is caused by a damaged boot sector, by doing what I´ve said in the first post you fix the boot sector and copy NTLDR from the CD to the HDD. it´s really not hard, just follow it step by step, this would also fix the problem of your "double C"-partition if it really exists, normally the drive letters are given automatically so there can´t be 2 partitions with the same letter.
and don´t worry, the badest thing that could happen is that you have to format the HDD and do a new XP install, you can´t damage the drive physically just by entering a wrong command.
just do it step by step:
- place the XP CD in the CD/DVD-drive
- while booting press "del" to enter BIOS (maybe F1, it´s announced on the screen)
- look where you can change the "boot sequence", set it to CDROM first, second C..
- save the settings and leave BIOS
- the system will boot from the CD now, you´ll be asked what you want to do, chose to enter the "recovery console"
- now you enter the commands from the first post, if you´re not sure what´s the letter of the CD/DVD-drive start with "D", if you get an error try "E" and so on until it loads the files from the XP CD.
- it should boot properly then
- if it works enter BIOS again at the next reboot and set the boot sequence back to C first....
