This sounds more like a corrupt profile to me than anything else.
I'm siding with this as cause (or) profile is very large in size making it inefficient and latent because of mechanical hard drive vs SSD.
Making a new profile for her to use and keep old profile remaining may be a solution. Browser favorites can be backed up and exported from old profile and imported to new profile. Personal data can be accessed through
c:\users\ and click on her profile name and should be able to navigate to locally stored data to access from outside of that profile from the new profile. A shortcut could be made to this data or it copied to a location that is not in the user profile to avoid the new profile from taking on large size. I like to save my data not within my profiles but at folders outside of the profile such as at C:\Data
If you do decide to go the route of an SSD upgrade though it can help in avoiding lag when dealing with large data as well as lag if there are many small files to be accessed. But a HDD is still usually plenty as long as you have adequate amount of RAM for the OS, where Windows 10 works best on 8GB or more of RAM and if 4GB RAM or less it can heavily page (virtual memory) working a hard drive to act as the extra RAM it needs to function better than no paging at all but this is where HDD's can become overwhelmed with read/write requests and the computer lags as its shuffling a flood of bits back and forth between system RAM and the HDD. SSD's are able to get data lightning fast vs having to wait for the data to come around on platters.
