Are any fans/lights coming on?
This may not be directly helpful, but...
Can you get into the laptop's BIOS setup? I think that's done with the F10 key at startup.
(The main thing that you'd learn from this is whether you have a hardware problem. If you can't get into the BIOS, things may be worse than a damaged Windows installation.)
Do you have a Windows 7 disc or a Windows 7 repair disc?