system restore

After a serious system crash I have re-installed my XP PRO including all
available updates. However System Restore became unusable. There are no
more restore points in the restore calendar and when I try to make a manual
restore point I get following message : 'System restore cannot make a
restore point now. Restart the computer and do System Restore again'. Doing
so doesn't help at all ! I do have enough disk space and the System Restore
settings are all correct.
I also tried by putting OFF the System Restore, putting OFF and putting ON
the computer and putting System Restore ON again. But it doenst't help
neither.
Any expert who knows the solution ? Many thanks in advance !

Martin-san