You can do one of two things: Best - follow firebird's advice to remove the entry.  Start, type in MSCONFIG, Boot tab, and delete the Default listing (since the default is not the one working).  The second should then be made the default (being the only entry). Next Best - if you are unsure which one to delete (if you delete the wrong one it is always possible to fix it), then you can right-click [My] Computer, Properties, Advanced System Settings (on the left), Startup and Recovery, change the Default Operating System under System Startup to the other entry, then change the Time to Display List of Operating Systems to 0.
When my computer first boots up, it stops at a screen that asks me what way I want to load my computer.  Both options say Windows 7.  The top one doesn't work properly and the bottom one does.  I have a feeling I put the disk in to download Windows 7 after I first got a new hard drive installed in my computer when I didn't need to.  At first I didn't think it was too much of a problem, however today it started automatically going to the version of Windows 7 that does not work properly, and it was very difficult to get back to the screen that let me choose.  I was wondering if there was a way to get rid of the version of Windows 7 that doesn't work without disrupting the one that does?
Problem with two Windows 7