Resume Download Files?

twclub

I download a file using Internet Download Manager,  when I downloaded 100% and start to merge the file.  At this time, the software crashes with something wrong.

Then I need to reboot my PC and restart the download manager. Since the file has been downloaded and under file merging only.

1. Thus, I would like to know how can I recover the file with merging again without to resume the file download start from beginning ah.....

2. How can I use Internet Download Manager as portable in my USB? I have this software with portable version (it claims), however, I find that it needs to install some files on PC. But public PC does not you to install anything.

Thus, I want to know how can I run Internet Download Manager software in my USB without installing anything in PC???

Your help pls pls pls pls ....