I suspect it has a virus; however, it is so unresponsive it failed to complete an online virus scan after leaving it on overnight. The scan was frozen on the file jscript9.dll
And are you using "real-time" security, or just on-line scanners? If using real-time (and hopefully you are), what program(s)?
If me, I might install that hard drive into another computer as a secondary
the boot drive) and then scan the heck out of it (with diagnostics suggested above and with all my malware scanners too).
How much free space is on that drive?
Any errors in Device Manager? The fact it does this during Safe Mode suggests if drivers, it is a critical system driver (since Safe Mode only loads the basic, essential system drivers).