If it is Windows do the following:
Go to START > SETTINGS > CONTROL PANEL
Look for SCHEDULED TASKS.
Create a new task such as ALARM CLOCK.
In the TASK tab there will be a RUN window, put in something like:
"C:\Program Files\Winamp\WINAMP.EXE" C:\MP3\WAKEUP.mp3
Where the first part is the path to where you have WinAmp installed or where you have Media Player installed. (Your choice of sound program.) The C:\MP3\WAKEUP.mp3 is tacked on to tell the program what sound to play. Here I used the example WAKEUP.MP3
On the SCHEDULE tab you set the time and frequency. If you pick WEEKLY you can set what days you want this to occur.
Once you have this all setup, change the time to a minute or two from the current time to be sure it will work. Adjust your volume accordingly.
I use THUNDER Storm sounds to wake me up. Set your player to REPEAT so you MUST get up to stop it. Set your volume such that it will wake you up, but not everyone else.