Vista won't load - only black screen with mouse pointer - HELP!

I have an Inspiron E1505 with Vista Home Premium.

I did download a new application 2 days ago and yesterday the machine froze.  I had to press the power button off/on.  Next time it came on said 'windows error during startup'.  Only options are 'load windows normally' or 'repair and restart'.  The repair and restart just loops - does nothing!  Start windows normally attempts to load, see microsoft bar and than goes black with just a mouse pointer.  I never see the windows Vista logo with music at startup.  

I did run a hard drive diagnostic and passed. I tried to do a repair with the Vista DVD and it's the same on reboot, black screen.  I have pressed F8 during boot and tried repair there, nothing.  I tried last known good config and safe mode, nothing.   I know I have backups happening but when I went to 'system restore' it said it could not find any on the machine.  I know they are saved to D: is that the reason?  There is no prompt to direct it where to look!

I just want to get to a point where I can remove last application installed.

Can anyone help!  I still have hardware warranty but not software.

If you give directions, please be specific I'm not a geek.

Thanks in advance for assistance!