From your OP;
The download will come up, then in the middle of it, it will tell me it cannot be downloaded.
Nothing to say that this is related to your internet connection, browser or security settings and after looking at your Speccy log I would suggest checking out your internal HDD as it is shown to be overheating, this could be causing the HDD to malfunction when under load such as downloading data to it;
The things from your Speccy report that may explain the download problem;
The HDD Temperature Range: Warning (50 °C to 55 °C) your HDD when not even under load is 52 °C
The output on the +12 V rail of your PSU is reading as being 13.440 V, the max is 12.600 V, the extra voltage could be what is heating up the HDD.
What I would suggest that you do;
Disconnect all of the following devices when not in use so as to ease the load on the PSU;
149GB Seagate External Drive USB Device (USB)
954MB Kingston DataTraveler 2.0 USB Device (USB)
29GB Lexar USB Flash Drive USB Device (USB)
1GB Multiple Flash Reader USB Device (USB)
Download and run the Data Lifeguard Diagnostic for Windows from
here, do the short test first and then the extended second, if the drive fails the short test it will most likely fail the extended test in no time at all.
I also noted the following in your Speccy report;
Windows 7 Installation Date: 7/26/2010 6:59:47 PM
Partition 2
Partition ID: Disk #0, Partition #2
Disk Letter: C:
File System: NTFS
Volume Serial Number: 54447CC3
Size: 917 GB
Used Space: 91 GB (10%)
Free Space: 825 GB (90%)
Can you tell us if this HDD has always been in this computer and how you have managed to use so little storage space after more than five years of use.