Hmmm... I'm not sure if this is the fault of Windows or not. To found out if it is or not, could you please do the following.
1. Download Ubuntu 11.04 iso image. Download | Ubuntu
The link gives you instructions on how to burn the iso to a CD with Windows 7. Download the 64 bit version of Ubuntu.
2. Burn the iso to a CD, and keep the CD in the disk drive.
3. Shut down from Windows. When Windows 7 appears to be shut off, but the power of the computer is still on, just pull the plug to disconnect the power.
4. Plug the power back on, turn on the computer.
5. Open the BIOS and make sure that the computer will boot off the CD.
6. Boot Ubuntu from the Live CD and it will load files a bit. It will then come with a screen giving two options. One saying something like Try Ubuntu, and the other Install Ubuntu. Just select Try Ubuntu. Wait for it to load to the desktop. Once you are in the desktop, shut off the computer from Ubuntu. You can do so from the very top right corner of the screen. Once Ubuntu shuts off, check to see if the computer power is still on or is off. Report back here when you have done so.