...I usually try to avoid anything that requires an install because by the time I get called in the machine in question is usually barely stable enough to run in safe mode.
Well, you could be proactive about it and periodically run Belarc Advisor on each asset (deskop/laptop) that you have to support - or, if not periodically, then initially at least.
That would give you a lot of the As-built(*1) documentation (the Belarc Advisor report with the various software reg. keys in it).
You would then have the relevant configuration item information to be able to rebuild that asset - without needing to wait to get that info till it fails.
Note: *1 - The 3 config. items in the CMDB per ITIL - hardware spec., software backup/copies, as-built documentation).