Could this mess up my computer?
you never know before you try 
http://forum.avast.com/index.php?topic=111332.msg874880#msg874880
[b]I'm seriously done with testing any new programs.[/b]
if you are afraid i suggest you follow your own advice (see quote above)
or get another comp that you are not afraid of breaking, so you have that to play with
So, it could mess up my computer? Yes or no? ???
No one is able to give you a definitive answer, they don’t know exactly what is on your system and how it might interact with the program.
If you don’t have a robust backup and recovery strategy (minimal hard disk imaging software or running a second computer as a test system or running a virtual OS on the existing system), experimentation is always going to involve risk.
Thanks for your reply.
I started to install it but when it got to the part where it said I would be disconnected from the internet I didn’t go any further.