Strange Behaviour

Hello,

I have a UNO that I have been using for quite a while. My programs typically load fully as indicated by the thank you at the end. However they seem to stop at a different point each time I load and run them. I also use the Serial Monitor to track progress by using Serial Print statements. One thing is strange is that the Serial Monitor is filled with lots of strange characters.

I am wondering if the program is really loading or is missing some parts and this is causing the strange characters?

I will gladly upload the code but I waited since it ran before and should still run so I feel it is something else.

I have replaced the USB cable twice without any change.

Any ideas of what I should look at?

Thanks in advance for your help!