same thing happened to me when a month after I bought my 97 lesabre used.
it could be a number of things
1 fuel pump, put your head near the gas neck hose see if you can hear the fuel pump engaging, if you hear it thats not it
2. starter
3.dead or weak battery
got to get it to a shop, tow it and find out what is wrong, that's what I had to do
