I tried gpugrid but something more than 2days is too many vor my windows box with its little 8600GS. I think the problem is that it is a OEM gpu wich has not enough power for crunching. The BOINC- and the gpugrid-client look like they are working good.

When i ever get a better gpu I will triy it again cause a gpu wich does nothing is not in my interrest.