HELP!!! Car won't start
 

i have 97 E320 w/ 107k mi. i was leaving shopping center and when i turned the key, it would crank like it wants to turnover,but it never did...my battery is good, plugs good, gas in tank...cant figure out...about 10 min later, i finally got it started. but after it turned over, its sounded like a jet engine,and gave a "vrooom" sound. any input or suggestions would be much appreciated...i was planning on taking it to vegas today, but im very hesitant cuz i dont want to be stuck in the middle of the desert. thanks in advance for any info...

thanks for the lead ben'z