70xx & 76xx WU's seem to be especailly problematic with this known bug. Still you do need to verify that it's a bad work unit, & not something else before dumping the work unit.
Checklist before dumping work unit:
1> verify that nothing else is hogging significant CPU cycles. Best way to do this (Windows 7 or older) is to open task manager, go to processes tab, select the "Processes from all users" option, then select the view menu & "Select Columns" check the "CPU Time" box then click on the new CPU Time headder to sort processes by most CPU Time used. After a week of "up time", I only have 11 processes with more than 1 minute CPU time & they're all FAH or Windows system related. Basically, you're just looking to verify that no process(es) are stealing significant CPU Time from FAH. This is one my biggest single gripes with Windows 8, they've removed this option... It is/was truly an invaluable tool for troubleshooting slow systems.
If you can verify that nothing else is hogging your CPU resources then, then continue to step 2, otherwise stop & fix your computer
2> report work unit to Stanford Forums, including Run, Clone, Generation data, and the first 5 - 10% of the FAH log for that work unit. Here's a bad work unit post I made a whie back that even shows what I'm talking about in step 1.
http://foldingforum.org/viewtopic.php?f=19&t=22821 3> Save the log files, in case Stanford wants you to supply additional information later. I save mine to an old 256MB thumb drive that I don't otherwise use anymore.
4> dump the work unit & enjoy the return to normality. According to Stanford, this bug causes the finished work unit data to be unusable to the project. So even though you can fold it through to completion, & receive points for it, the effort is 100% wasted time & work.