This would have been great if i could get into the BIOS to change the boot order so i could set CD to boot before the hard disk. Unfortunately BIOS would not let me in as it was not accepting any keystrokes on boot. After exhausting almost every option and beginning to take the laptop apart to remove the CMOS battery in the hope the default setup has Cd boot before HDD i thought, i know, i reckon a Linux live Cd could sort this out. I had tried windows 7 and Windows xp CD's but neither would read the hard disk in the laptop
I had to remove the hard disk and put it in another laptop, then i could boot from a Live Cd and fix the MBR.
i used an ubuntu 8.04 cd in the end which had almost everything i needed. I had to install lilo to write the boot record as ms-sys was not accessible due to Microsoft making them pull it from the repository.
lilo can be installed with something like
sudo apt-get install lilo
after this is installed you need to find the partition with the mbr. This can be seen with the following command to list hard drive partitions
sudo fdisk -l
once you know the drive with the boot sector you can then do something like
sudo lilo -M /dev/sda mbr
This will overwrite the MBR. after this had run i put the hard disk back in the existing latop and it booted back into windows 7 with no problems.
thanks again Linux! so many times you have saved me!