Please forgive me for posting this in a professional forum. I have been searching for help for weeks and no one will answer me anywhere else. After many months of using Windows 7, I was using Backup/Restore to make a Disk Image, when I began getting errors. The process would not complete. I got the typical I/O error message code about a problem with the device. I decided to copy my important files and folders manually to my external drive. Then, I began getting freezes during the file copy operation when copying files over 1.5 gig or so. If I clicked "cancel" in the file copy dialogue box, the system would hang, with the "cancel" animation just playing over and over again for hours. Then, I tried just to copy a large file *partition-to-partition* -- again, the copy process hung the machine. I've run the File Tools to check the drive and fix bad sectors on both my internal C and D drive, as well as my external hard drive ( there is plenty of space on all drives). And, when I do copy a large file partition-to-partition, the file copy begins very fast, but then slows to under 1 mg a second, then slower and slower until it just hangs the system. I've tried all the above operations from Safe Mode -- same results. I've tried turning off Avast completely. I even uninstalled it using their uninstaller, then did a fresh install -- same thing. I've turned off "thumbnails" so only icons show up to avoid any additional strain on the system -- dunno if this makes a difference. [added later today: I would like to add that I am able to copy even very large number of big files from my digital camera chip if I plug it in my computer's SD reader] 1. Can I refresh/renew all the critical Windows files WITHOUT reformatting and reinstalling Windows? 2. Why should this happed suddenly, after many happy months of using my machine?

1. First of all look into Event logs and reveal your finding - errors and warning are important for troubleshootin 2. Run the folloving with elevated rights (right click on Command prompt and click on Run as Administrator) sfc /scannow 3. Test you memory and hard disc (program memtest for memory and disk vendor's test program for HDD) 4. When you run into problem like this one, start Task Manager and see what the load is 5. There are more tools to recover system behaviou, namely the Perofmance Monitor. 4. You may try to recover your system by starting installation from Windows installation media, but choosing UPGRADE instead of new clean install. (This procedure removed IE 9 in my case and nothing else.) Regards Milos