no graphics shown

hi all,
i installed boinc a few days ago, everything worked fine (including graphics) and i was quite happy. but since today graphics in screensaver mode won´t work, just the boinc logo appears...and in the boinc manager - work show graphics first of all is not grey, but after clicking a few times, no graphic appears and it turns grey...as i told, it worked for a few days, i didn´t make any changes on my system in this time...any ideas??

i installed single user mode, on my winxp pro sp2...

system:
dell inspiron 8200
geforce 4togo, 64mb ram
system ram 512mb
40gb hard disk

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