Hi @ben_fu
Thanks for the question
You simply need to install MT4 again in a different location. Please see the below steps:
Download MT4 setup file from the following link and run it: http://www.ig.com/content/dam/publicsites/igcom/mt4/ig4setup.exe
Tick to agree with terms > Settings:
Browse > Expand Desktop* > Make New Folder and name e.g. 'IG MT4 2' > OK > Rename Program group e.g. 'IG MetaTrader 4 Terminal 2' > Next:
Finish:
I have added some screenshots below which should help.
All the best
Anda