Major system malfunction. System details at end. Sequence of events was: 1. Download update from A-Square Free. The update was strange in that it was one file rather than the usual download of many small update files. File size about 36 MB and it took about 45 minutes to download. I thought it somewhat unusual but didn’t think too much about it. 2. Ran A-Square Free. It found a small trace of something and listed it as a medium risk. Deleted the specified file. 3. Attempted to launch another application and found to my shock that most of my apps were missing!!!! 4. Hot re-boot… Oh NO... hal.dll is missing or corrupted. NO Windows load at all. Cold boot same result. Not even startable in Safe Mode! 5. I’m seriously, seriously dead in the water and looking at a complete rebuild. Praise the Nine Lords of the Universe, I use Acronis and simply rolled back to previous backup with minimal loss. Note: the only new application on the system was Ubuntu, which I was experimenting with. I was in Windows rather than Linux mode at the time of the system meltdown. WHAT HAPPENED? I need to know so that I can avoid the same problem in the future. System: Win XP Pro SP3 Intel Dual Core chipset Dual 300GB drives plus Tbyte external drive Lots of apps but reasonably vanilla system. Full time security…NOD32, current version and up to date; Online armor (HIPS), old version 2, not up to date, all modules inc. firewall turned on.