Transferring Files to Computer causing issues

hey guys so today my user account became corrupted somehow and before I deleted it, I transferred all my documents, pictures, music, and videos to my external hard drive, well after i created a new user account and inserted it into my computer so it wouldn't become corrupted and started transferring my files to my new user account things on the whole system became very, very slow and when i hit cancel my entire system went fast like it normally should, I don't know if this is a problem with the external hard drive or my computer any help would be appreciated thanks for your help guys

Click on hard disk drive- properties-tools-check now on error checking-
after it completes do disk defragmenter.