Really there are no easiest options. I am not saying that to be a wise-guy, it's the truth.
Please do not confuse (Windows 7) Operating System Updates and (Windows 7) Device Driver Updates.
The IObit Driver Booster will not help you in any way as far as (Windows 7) Operating System Updates go.
Before we go too far, in your 1st. post you show Setup Failure screens from a 32bit. version and a 64bit version. Please make sure that your computer supports 64bit. software.
It is recommended and less headaches to install programs on the same drive as (Windows 7) Operating System (in your case Drive C:\)
Another point to consider is (Windows 7) Operating System requires free space to correctly run. I think everyone refers to 15% of hard drive capacity.
For example... If your hard drive capacity is 1 terabyte using a 15% recommended free space means that your system would need 150 Gigabytes of free space. That may seem a bit of overkill but it is a recommendation.
It looks like you have a bit of work ahead of you before downloading and installing anything. A recommendation would be to store your Documents, Music, Pictures and Videos on a seperate drive or partition.
Should you decide to follow, once you have your Documents, Music, Pictures and Videos removed from C:\ drive, run Disk Cleanup and see if you have enough space to install Windows 7 SP1 (windows6.1-KB976932-X86.exe) and the Convenience Rollup (April 2016) Update for Windows 7 (KB3125574) and Microsoft Visual C++ 2015 Redistributable (x86) - 14.0.23026. In that order.