It is difficult to help you. There is definitely something off with your computer. I do not think it is from RStudio.
You should try uninstalling again, then restart completely, then reinstall from scratch.
Sorry, I know you may have tried that already but not sure how we can help you more.
I solved my problem. For information, it was my antivirus who killed the process everytime I launch RStudio. Add an exception on it solved the problem.
Thank you again for your help. This topic can now be closed