I am not sure if this has been shared before, but I just learned this the other night. I cannot take credit for this info, but those that shared it, know who they are. I hope this helps. Cheers. (Just for those that want sources.....this is an internal memo and all names and proprietary references have been removed)

Windows XP was designed to be able to handle multiple users. Therefore each user has their own space for savings their attributes (desktop preferences, security, etc.) For this to function correctly the user must enter and leave the system in an orderly manner. Then only the pertinent files are saved in each users space. Power failures, incomplete installations that hang the system and improper power off sequences are some of the ways that the users personal space becomes full of unneeded files. Unfortunately, the system has no option but to scan this file space and look for a coherent set of data files when a user logs into the system. It appears that all files in this directory structure are opened on a login or a boot cycle process. So you can get a very slow boot or login process. Now for the good part, this folder is HIDDEN. So you have no easy visibility into this folder becoming more and more packed with unwanted files and then the boot process slows down more and more. I would suggest that you do NOT allow viewing of Hidden and System files and folders by the user - the default is that they are hidden. The easiest way to find this folder structure is to go to MY COMPUTER and search for files or folders named TEMP. Be sure to select Advanced Search option and check the box for Hidden Files. Of course you will get a lot more than you want, but near the beginning of the Search Results, you will see a list of search results such as: A folder called TEMP in C:\Documents and Settings\XXXXXX\TEMP - where XXXXX is the user name (Owner - Administrator - or - Default User, etc. Open these Temp folders by clicking them (this is like an HTML page) and you can delete all of the files. The files that aree needed for this boot or login sequence will be OPEN and you won't be able to delete them I have tried this on multiple PCs that were booting up slowly and it works. So, give it a try. These folders are also present on WIN NT and WIN 2000 and serve the same purpose. Another facet of Win/XP is that serious errors can be recovered. This is accomplished by creating a dump file and rebooting - from the user's perspective it looks like the PC boots up twice and has a dialogue box open that tells you a serious error has occurred. Those Dump files are written in the folder:C\WINNT\MiniDump This recovery process can be recursive if the settings in the (possibly corrupt) user's folder can not be reconciled with the current operating environment. An example of this is files on a removable disk (for example: IOMEGA ZIP Disk) that were open by the system or an application or pointed to by "dirty" disk cache buffers and when the PC reboots the drive medium is either missing or different from the expected Volume name. You can turn off Write-Thru Caching if this is a bigger problem than the slower performance would be with this option off. I would suggest that if you are going to use the Hibernate option of automatic shutdown that you do turn off Write Thru Caching. The possibility exists that there will be a race condition where the PC actually goes down before the buffers are written. You can open and examine those MiniDump files.