Re formatting Acer Aspire 1800

Hello,
I want to reformat an acer aspire 1800. the 1st problem the system goes into checking file system mode on partition "D" and it takes a day or more to complete the scan; then it starts to boot up and keeps booting up. It's very slow. I shut down the pc and put the recovery cd in but it the system goes back to the same scan screen again. It's doesn't booting up from the cd so I can reformat the drive. Am I doing the right thing or is there something I'm doing wrong?