Just in case if you have not known, before the Avast 7 beta, I had reported an issue with avast's rootkit protection code in aswSP.sys causing DRIVER_UNLOADED_WITHOUT_CANCELLING_PENDING_OPERATIONS blue screens when avast is installed on a computer with programs such as Citrix's ZenApp Offline and Online clients, Trustware's BufferZone (in case if anyone wants browser sandboxing as avast! free only does sandboxing for malicious applications), and Jetico's BestCrypt (file encryption software). The bottom line is that avast! seems to be deeming drivers that hook into the kernel in a certain way as rootkits and unloads the drivers, creating a false positive. Therefore, during the testing period for avast 7, a rootkit protection improvement or revamping may be needed.