How to run the robot regularly on the normally use machine?

Hi all,
I want to automate processing to the robot at the terminal used for business processing.
Although mainly using Excel, in UI operation such as button click from ribbon menu, data scraping from Web,
There are many processes that can not be achieved with ExcelScope alone.

In this case, do I have to prepare a dedicated PC to run the robot?
Is it necessary to operate via COM in order for PCs that are normally used to concurrently serve as robot operations?

Thanks in advance.