virus not detected and coloured lines on screen

hello ,some days ago i had a screen virus that block pc asking money as bribe for unlock it,it isnt detected from avast so i fixed it manually blocking it in msconfig boot,problem is from some days days randomly 1-2 times per hour come up a screen with lines coloured that last less than 1 second i was thinking it could be Ram issue and used memtest86(no error found),also i tested my grafic card temperature and all and no issue its all perfect so i think its still a issue of this virus.
I done a fasts search for virus with avast and found 2 infect files but in log there are not quarantine files and it say no virus found…but still 2 file infect ,doing more search its same i got 2 infect files but cant remove them or find our folder …

anyone could help me?sorry for bad english

virus name is wpbt0.dll tried remove manually it started recycle.bin and avast blocked and put in quarantine but file wpbt0.dll is still there

You could send the undetected virus file to virus@avast.com keep file zipped and password protected…specify password in e-mail…

follow this guide: http://forum.avast.com/index.php?topic=53253.0

attach all logs here…

hmm…Looks like ransomware and fakeAV’s are on the rise… somebody secured their credit card processing systems… ;D