Hi andrescs, thanks for your help!
I confirmed that .libpath() for both is separate, going to 2 separate folders named 'C:\Program Files\R\R-3.X.X\library', respectively.
For R-3.3.3, I have a folder named "tidyr" that has updated content since I last executed an update. I ran
> install.packages('tidyr', `update.packages(checkBuilt = TRUE)
and was prompted to hit "Y" for a number of packages and updates but the updates froze when it got to 'tidyr'. I let it try to finish updating for several minutes but seemed permanently frozen as I've seen before.
For R-3.4.2, I do not even have a folder named "tidyr", but instead I have a list of folders named something like "file77d413ac7710" that corresponds to each time I have tried to install tidyr while running this version of R.
Inside there is a folder named "BH" and inside that a list of 4 folders and a handful of files. When I compare this to the contents of the 'tidyr'-folder in R-3.3.3, all the folders in the R-3.4.2 tidyr folder are in the R-3.3.3 folder but R-3.3.3 has a few ('data', 'demo','doc', and 'R'). Also, R-3.3.3 does not have an intermediate "BH" folder.
I noticed part of the error message when installation of 'tidyr' freezes is saying that "Rtools" is not installed. So I tried installing 'Rtools', but got a message saying Rtools is not available for R-3.4.2... I got a similar error message when I downloaded another package ('cowplot'), but that installation still completed without freezing my lap top.
Any other ideas or help would be greatly appreciated - thank you