My OfficeLibre 5.1 won't open

I installed LibreOffice 5.1 about 3 weeks ago; used Writer almost exclusively; & I was very happy with its performance. While I realize there are likely more current updates, since I’m running an outdated computer with Windows 7 SP1 (64-bit) OS, I just needed this office suite to function until my Tax Returns are finished (when I will switch to a more current PC.) However, perhaps coincidentally, about 10 days ago I stupidly installed the ESET Nod32 anti-virus program. After running a scan, it showed a PUA (Potentially Unwanted Application, namely, Slimware) which ESET recommended removing (not a straight-forward task).
Q1. Do you think this PUA could have had anything to do with LibreOffice failing to open?
Q2. Ideally, I’d rather try to continue with LibreOffice IF it’s fairly straightforward to figure out how to open it. Any thoughts on how to do this?
Q3. But if my computer is too much of a mess to “fix” LibreOffice, I may have to uninstall Libre instead, and install a subscription I have to Microsoft 365 (Word, Excel, etc.). If I go the path of switching to MS Word, will the LibreOffice Writer files that I saved earlier remain in tact? Many thanks!