Something funny has happened to my computer?

I dropped my USB on the floor and when I plugged it back in, it simply didn't work. Normally it would flash when it was inserted but this time it didn't. I attempted to recover some work that I had done on a Microsoft Works Spreadsheet by using 'open with' but this didn't work. I then played solitaire and then switched the computer off. Next time I used the computer, all the programs instead of having their usual icons had the Microsoft Works Spreadsheet icon and wouldn't open. The only program that worked was solitaire. A message kept coming up that the programme was a read only file and that it couldn't open it. In desperation, I went to the control panel and created another account and the programmes all worked on it. Can someone tell me what's happened? What can I do to fix it? Would it be safe to delete the original account and just use the new one I created? Another thing is that I accepted the terms and conditions for Microsoft Office 2010 on the new account too- is this ok? Thank you!