After running defrag I am having following symptoms: most of the automatic services don't start and I can't start them manually, only 20 services start automatically, I can't access services properties, the pane with the Extended Services only shows a blue square in the upper left corner, System Restore doesn't work and I can't get it started - "System Restore is not able to protect your computer" I tried all the possible ways to get it to work. My Internet doesn't work, Firewall doesn't work, printing doesn't work, Windows Explorer works but I can't copy and paste (paste is greyed out), the Search function doesn't work, my e-mail works only in the receiving direction - I can't send anything out, some programs work, some don't. I uploaded the Recovery Console from my XP CD and it works fine - I disabled Trend Micro antivirus services to see if it's not a culprit, nothing. I can use RUN command. I pulled my hard drive out and checked it for viruses with Trend Micro and AGV - no viruses, I ran CHKDSK - nothing wrong. When I use my old Windows XP CD it gives me an error message saying that my OS is more recent (SP3) so the XP Setup will not start. I think some system file or registry got corrupted during defrag. Can someone tell from above symptoms which file I need to expand from the XP CD using Recovery Console? With my hard drive hooked-up to the other computer I can also manually swap files in WINNT directory and could use files from all the downloaded updates to OS instead of the old files from the CD. The only problem is I don't know which ones I need.