I am running Win7 64-bit on a Core i5-2300 with 4GB RAM.
On 2 occasions I have noticed an elapsed time of over 12 hours, and only "---" for remaining time for 4 WUs running simultaneously. Both times I stopped Boinc and restarted it again. After this the WUs started from 00:00 elapsed time and showed a remaining time of around 16:00 (didn't take note exactly). The first time the WUs went on to finish, the 2nd time was a few minutes ago and they seem to be progressing normally.
Any ideas? Anyone else seen this?
Edit: Unfortunately I didn't notice what the Progress percentage was.