LibreOffice Calc 4.1.2.3 'Not Responding'

LibreOffice has generally worked OK for me, running from a USB stick inserted into various PCs, as designed.

However, after upograding to v4.1.2.3, I cannot load Calc files on my main Win7 Home 32-bit desktop (though everything works fine if used with a Win7 Pro 32-bit laptop). Calc 'Not Responding' (and never does); the CPU is only idling.

Bizarrely, this behaviour persists after complete uninstalls/re-installs even of previous versions of LibreOffice (that worked OK before!).

Clearly, something in the OS environment on my main PC is responsible, but what? Both PCs are fully patched; and isn't LibreOffice supposed to be fully self-contained?

Any clues as to what might conceivably be the issue here would be much appreciated.

Edit:

01. 'Writer' works fine; it's a 'Calc' problem.

02. Installed v4.1.2.3 to a folder on the hard drive of desktop; same issue, so it's not a USB stick problem.