You may find that your ISP as a time limit or no activity cut-off. Best to check your terms and conditions, especially if it is PAYG. If they have this, then you may well find any long downloads will not succeed, unless they have a resume in the downloading. There are programmes available, but I have never known anyone who as used one. Your could try click here who seem to have a good range of freeware/shareware programmes available. Even PCA may have a programme in the download section.