Usually the correct way to remove your Windows partition is to use the BootCamp Assistant again which should give you the option to remove the made Windows partition and revert back to one OSX volume.
After that's done a reboot of your Mac might be advisable. After the reboot use the BootCamp Assistant again to make the Windows partition and then install the (hopefully correct) version of Windows.
Only if that's not working (whatever the reason) :
1) boot your Mac from your OSX install DVD
2) choose your language and then 'ignore' (cancel) the installation
3) from the Top Menu (Utilities) start Disk Utility (DU)
4) in DU click on your harddisk (not any partition) in the left pane (the first item listed)
5) in the right pane use the 'Partition'-Tab
6) click to highlight on the ex-Windows partition you want to delete
7) click on the small '-' Button at the bottom
That should delete your former Windows partition
After that's done successfully
8) Drag the partition separator line until it encompasses the entire drive and then select apply.
9) Quit Disk Utility
10) reboot your Mac from your harddisk.
Since you are 'fumbling' with your OSX partition you should consider having/making a backup of it before trying the a.m. procedure. Just in case.
Usually the correct way to remove your Windows partition is to use the BootCamp Assistant again which should give you the option to remove the made Windows partition and revert back to one OSX volume.
After that's done a reboot of your Mac might be advisable. After the reboot use the BootCamp Assistant again to make the Windows partition and then install the (hopefully correct) version of Windows.
Only if that's not working (whatever the reason) :
1) boot your Mac from your OSX install DVD
2) choose your language and then 'ignore' (cancel) the installation
3) from the Top Menu (Utilities) start Disk Utility (DU)
4) in DU click on your harddisk (not any partition) in the left pane (the first item listed)
5) in the right pane use the 'Partition'-Tab
6) click to highlight on the ex-Windows partition you want to delete
7) click on the small '-' Button at the bottom
That should delete your former Windows partition
After that's done successfully
8) Drag the partition separator line until it encompasses the entire drive and then select apply.
9) Quit Disk Utility
10) reboot your Mac from your harddisk.
Since you are 'fumbling' with your OSX partition you should consider having/making a backup of it before trying the a.m. procedure. Just in case.