I switched to Linux then back to Windows, and now I'm trying to go back to Linux again. But somewhere I messed up. Now Linux won't install, saying ext 3 cant be created. Also all my partitions are gone for some reason. Any suggestions?

So Windows still boots? What are you trying to do, erase your hard drive and everything on it, and just single-boot Linux? Or are you trying to dual-boot between Windows and Linux?

If you have a Linux prompt, post the output of this command:
If you've got a SCSI or SATA drive, replace 'hda' with 'sda'.

Windows doesn't work, for some reason. The partitions are gone and I cant get anything to install. I just want to single boot Ubuntu. Do you think my hard drive died?

Get a Linux terminal open. Try writing zeroes all over your disk first:

Now that your hard disk is erased, try starting up the Ubuntu installer and see if it will let you create an ext3 partition.

using a live disk can u mount your hard disk. is it accepting the mount partitions and showing anything atleast??

Every time I try to mount the hard disk I get nothing. The message I get is ext3 file system in partition #1 of IDEI master (hda) failed.

Did you try erasing your hard drive and recreating the partition table, and finally reformatting the partition(s)?

How do I do that?

Boot into recovery mode off of a Linux CD.

To erase your hard drive:

To recreate your partition table:
Then create your partitions, write to disk, and exit.

Then reinstall Linux on the newly-created partitions, and make sure you tell the installer to reformat the partitions one more time. And for good measure, make sure to install your bootloader (usually GRUB or LILO) to the MBR (which is usually the default behavior).

I tried the command
dd if=/dev/zero of=/dev/hda

but i got an acess denied after hitting enter.\

Also I couldnt find a recovery mode on the Ubuntu main menu of the live cd.