So this is only compressed files with .zip, .rar, or.7z extensions? Odd. Did you change, or add any security programs about the time this began? Some programs may be set to block certain file types, or attempt to scan within archives, and this would certainly delay a download, especially on slower connections.
Try this, make sure the file is from a trusted site. Boot to Safe Mode with Networking, and attempt to download the same file (.zip, .rar, .7z). See if the d/l works in safe mode. Safe Mode