1. Firstly check whether the port available by default 8080 is open or not. Use telnet to check this.
2. Look whether tomcat is getting restricted due to firewall / antivirus. If possible, disable these temporarily and start tomcat.
3. Download a fresh version of tomcat and deploy BO warfiles.
4. If new tomcat starts post step 3, but you are not able to view CMC / BILaunchPad page. Repair the installation.