I had Windows 7 on my laptop (factory setting), because of some performance issues, I decided to use recovery options to restore it to its factory condition but I don't know what has happened or what I have done that the whole operating system was gone after playing around with recovery options from the boot menu. I couldn't find Windows, so I installed Ubuntu 11.04 on my laptop. Last time I had Ubuntu on it, it was not really compatible with laptop's configuration and I had a bit of problems trying to do normal tasks I used to do on Windows. Now I want to make sure that Windows and its drivers are gone so that I can try to install a newer version of Ubuntu or Windows. I tried the command

 sudo fdisk -l

And the result shown was:

 myaccount@myaccount-VPCS116FG:~$ sudo fdisk -l
[sudo] password for myaccount:

 Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00025b5f

 Device Boot Start End Blocks Id System
/dev/sda1 * 1 38409 308515840 83 Linux
/dev/sda2 38409 38914 4052993 5 Extended
/dev/sda5 38409 38914 4052992 82 Linux swap / Solaris

Disk /dev/dm-0: 4150 MB, 4150263808 bytes
255 heads, 63 sectors/track, 504 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa668cfe8

Disk /dev/dm-0 doesn't contain a valid partition table

Is it gone? If not, what command should I try to have access to Windows partitions? Thank you.