I assume you are on windows XP... The PC may have moved the pictures to your "My Pictures" directory... But that is a guess, if you used the software that came with the camera it could be in other places. To check there you just need to open up your My Documents, usually there is an icon for it on the desktop/background. If not click on your start button and see if it is listed there. Once in My Documents you will see a My Pictures directory, and that is the first place to look.
If that does not turn them up, then you can search your hard drive. Click on Start -> Search --> in the left column look for all files and foldres (or you may see this in the right hand pop-out), select that --> you should see an option for Look in now, do "All Hard Drivers". In the box under "All or part of the filename" do a search for *.jpg
This will search out all the pictures on your PC, and tell you where they were found. You may end up with a lot to look through, but should find it.
Lance