Hi chaps... This is a sort of last hope request, I am trying to run sfc / scannnow on my xp pro sp3 p.c..... (was fully uptodate until end of updates from ms). I am getting the dreaded "Files that are required for windows to run properly must be copied to the DLL Cache. Insert your Windows XP Professional CD-ROM now." This may have said xp pro sp3 cdrom before some of my changes..... (sorry really late night trying to figure out the problem). Things I have checked so far.... Used my XP Pro install CD.... (I know it's the correct one as I have the date written on it when it was last used to install). ran regedit and checked here.. HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup (to make sure correct CD, it wasn't so I changed it to correct one). No effect same problem, after reboot. Downloaded "Windows XP Service Pack 3 Network Installation Package for IT Professionals and Developers" and unpacked all of it to C:\... went back to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup changed it to look at C:\.. No effect same problem, after reboot. back to regedit and changed HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon - Set SFCDisable to 0 or 4 "I used 4 to disable the popups".. No effect same problem, after reboot. here is the print from msinfo32, I'm hoping it may help. OS NameMicrosoft Windows XP Professional Version5.1.2600 Service Pack 3 Build 2600 OS ManufacturerMicrosoft Corporation System NameSANDY-7DA80DB05 System ManufacturerGBT___ System ModelAWRDACPI System TypeX86-based PC Processorx86 Family 6 Model 10 Stepping 0 AuthenticAMD ~2086 Mhz BIOS Version/DateAward Software International, Inc. F5, 27/08/2004 SMBIOS Version2.3 Windows DirectoryC:\WINDOWS System DirectoryC:\WINDOWS\system32 Boot Device\Device\HarddiskVolume1 LocaleUnited Kingdom Hardware Abstraction LayerVersion = "5.1.2600.5512 (xpsp.080413-2111)" User NameSANDY-7DA80DB05\Sandy Time ZoneGMT Daylight Time Total Physical Memory2,080.00 MB Available Physical Memory1.26 GB Total Virtual Memory2.00 GB Available Virtual Memory1.96 GB Page File Space4.85 GB Page FileD:\pagefile.sys I was really hoping to have figured this problem out for myself but I know when I'm beaten.... If anyone could help me out I would really appreciate it. I really don't want to do a re-install as I have a lot of programs that I use every day,... and I understand why some people may say "stick win7 on it" but I already have win7 on 2 other p.c's and a lappy. one other thing is that about a year ago I was nearing a HD failure so I did a ghost and put it onto the new HD and everything went fine. But I now seem to be getting some unusual errors from explorer.exe and a few other files. I have ran antivirus, and 2 lots of antispyware on this and it checks out clean as a whistle. SO I just wanted to check the file system, so here I am asking for help.. thanks for looking chaps... sadsack