Could any one help me about this...

Is there any problem if I will upgrade Oracle 7.3 to oracle8i or beyond. We're using oracle 7.3 for 6 years and I want to try new version of oracle database, but i'm worrying about my current database stored in the lower version. If I upgrade it to new , will I encounter problems , I mean, if I have an existing system running does it affect the whole system or still the same....I tried installing oracle8i before but I'm having a hard time to configure it. I'm using windows NT Server and Oracle server 7.3 , Do oracle8i have the option that you will upgrade it to advance version of oracle, I'm scared if I install it directly to my server co'z it might crashed the existing database.....I hope you could help me about this.. I don't have any knowledge in installing oracle8i....

thanks...