(I posted this here and not in the software section because I don't think the problem lies in the SP2 as such, though I might possibly be wrong?) This is not the rig in my specs but one of my pc's at work. I'm sorry for the long post but it's better if I write everything since in the situation I currently am every bit of information might be relevant. So, a couple of months ago a friend of mine gave me a pc to repair because it didn't POST. After checking everything I examined the motherboard closely and found a burnt voltage regulator module near the DIMM slots. I changed the motherboard, put the same processor and heat sink, connected the same RAM, video card, PSU etc etc, the pc worked and I gave it back to my friend. Now one of the things I had done while repairing this pc was to take a DDR 266 RAM module from the work pc and try it on this pc, to check if it worked with different RAM. The RAM modules on the friend's pc were DDR 400. At that point so far the work pc was OK. Then the following day I didn't go to work. And things happened when I wasn't there... My dad switched on the work pc, and thought it was running too slow on just one 256MB RAM, so he took a 512MB Module from my friend's pc, found that it physically fit in the slot and inserted it. After he did so the work pc didn't POST either. Now the motherboard of the work pc is (was!) K7VT2 ASRock Mobo ( http://www.asrock.com/mb/overview.asp?Model=K7VT2 ), supporting only up to DDR 266/200......... whereas my friend's P4 from which my dad took the module to insert in the Athlon work pc had an ASRock P4VM800 Mobo and the DDR Module in question was DDR 400....... Anyway, I took the work pc home and tested everything - tried different RAM, tried another video card, tried a different PSU, disconnected all drives and removed all miscellaneous cards, resetted CMOS, whatever... Nothing doing, pc just didn't POST, exactly as my friend's pc had done. At the end I purchased another motherboard, took everything out and put it all on the new motherboard and everything worked perfectly so far. I did a Windows Repair (OS is XP Pro), thankfully I didn't lose any important information like taxes, wages and that work stuff... and so far so good. Then I connected the pc to the internet to download SP2. Downloaded it... OK Started installation... OK After 7 or 10 minutes in the middle of the 'installation', the monitor went blank, the pc rebooted itself, I got a message that SP2 had not been installed, and that any changes made were going to be rolled back. I tried installing SP2 some... 99 times so far I turned off automatic updates, removed the SP2, downloaded it manually, started installing and the same thing happened. I took the side of the pc off and put a house-fan blowing straight inside just in case it was over-heating - in vain. I ran memtest for some 4 hours with no errors. I ran orthos for some similar number of hours with no errors. I checked the hard disk with various programs... I replaced the video card with another one... I put different RAM... I tried another PSU... I tried installing from a Windows XP Pro CD which had the SP2 on the same CD - I got the message that I couldn't log in before I validate Windows - and I can't validate windows unless I get on the internet and to get on the internet I had to log in first! I spent hours trying to get out of that cycle. We are still using the pc for work, mainly we use it only for emails and Microsoft Office. It's got a fully functional Kaspersky and Spyware Doctor running. There are definitely no viruses or spyware according to those programs. Periodically I try to 'install' SP2 - the pc just reboots after some minutes and any changes are rolled back. Now it's constantly bringing up messages that 'this version of windows is not secure, please download and install SP2 now'. Also, I can't keep windows updated since most of the recent updates require SP2. What's worse is that although my dad had originally been the one at fault since he meddled inside the pc and spoilt the motherboard (and he might have done other stuff he didn't tell me about), he is now nagging me about this whole issue. Like telling me that I'm the pc expert, that I took the whole pc apart and rebuilt it and now I'm the one not capable of installing a simple XP upgrade and all that sh!t... [Rant warning] Hell recently he put in the TV card the pc had before and it didn't work (probably because it has to be enabled in the BIOS) and guess what he did - he took a connector wire, plugged in one end to the output of the card and the other end into the output of the motherboard sound........ while the computer was switched on. I thought we'd be needing a new mobo but thankfully the pc just rebooted, I pulled the cable out and it worked. Just so you know how my dad invents his 'experiments'. And he doesn't appreciate that I brought this pc from "non-running status" to "running and functioning with no data loss status", he keeps saying that the pc is worse than it had been before (HE) did the damage!!! [End Rant] Anyway. Thank you for having the patience to read all this, and I'd be grateful for any ideas you might have in getting an effin' SP2 installed on that pc! For reference purposes, in the image below you can see the specifications of the pc, and I am also attaching a dxdiag report just in case. Thank you!