Harddrive is making my system very slow and is not recognized

[rite2salil]

I recently installed dropbox on my external hard-drive since it is 1 TB and then one day my harddrive stopped being recognized by my computer. I tried it with a mac and it is recognized. I am able to copy files but I am not able to delete the dropbox folder. Also, when I connect my harddrive to any other systems (windows), it makes the computer very slow. Is there is anything that can be done besides formatting.

Thanks for your help in advance,
Sam

 

[rite2salil]

It is a seagate external harddrive. My USB cable is okay. Since I am able to see and open my folders in a mac.

Can my drivers be messed up and still somehow work with Mac.