Microsoft Works refreshing

In using a spreadsheet on my Windows 7, 64 bit computer, the program constantly refreshes or reboots when I bring it up to display. I can use it but it constantly refreshes (hourglass icon) and makes it irritating to try and use it. I don't know how to re-install it either as it came with the computer as it wants me to insert the disc with the program on it. This has just started doing this...