XP Rolled Back & Lost My Files

My PC was setup with 256MB RAM and Windows XP. I pulled out the two 128MB DIMMs and replaced them with two 1GB DIMMs and restarted the machine. The PC ran great. It was fast and everything appeared to be fine. Then when I told Windows to Shutdown, a screen came up and said that updates 1 - 30 were installing. I knew something was wrong because I didn't have Windows Automatic Updates set to install updates on shutdown. It had been set to download updates, but not install them until I said so. I also know that I wasn't 30 updates behind.

The updates completed and my PC rebooted, but immediately, it wasn't right. The PC was terribly slow. I'd press CNTL-ALT-Del to try and open the task manager and even after two minutes, the task manager wouldn't open. All apps were slow to open. Out of frustration, I hard booted the PC a couple of times, but the problem persisted. The other thing I started to notice was that the apps didn't seem right. Apps that I hadn't used for years were there, but apps that I'd been using the day before were gone. My anti-virus said it was way out of date, but when I tried to get it to update, it failed.

I went into the control panel and started uninstalling apps that I didn't need, in hopes that one of them was causing the problem. The anti-virus app wouldn't unininstall, claiming that a service it used couldn't be stopped. I worked on uninstalling apps for a while and finally got the PC to where it would boot and run okay. At one point though, I started the PC and was opening and closing various apps and Windows said that I was out of virtual memory. I used to get this error sometimes when I had 256MB of RAM, but it didn't make sense to me that it would say that when I had 2GB of RAM, when Windows was set to adjust the page file automatically.

Yesterday, I turned it on to work on it some more and I found that all of my apps, pictures, movies, and files dated newer than 2006 were gone. As one example, I bought a new digital camera in August 2008 and installed the software for it. All of that software is gone as well as all of the photos I took with that camera. All of the photos I took with my previous camera after 2006 are also gone, but the photos from 2006 and earlier are still there.

I ran several undelete utilities trying to get my photos back, but none of them found any trace of my files or applications. They all found undeleted files from 2006 and ealier, but nothing newer. It's as if my hard drive rolled back to a 2006 restore point and my 2008 files and apps never existed.

How could this happen? I know that when you add more RAM, the page file automatically grows, but that doesn't explain how my apps and files disappeared. All I can figure is that somehow Windows rolled back to a previous restore point. Sometimes when Windows does updates, it stores the last state in case you want to rollback the changes. What I'm wondering now is whether there's a newer restore point, so I can roll forward and get my apps and data back?

Where could I look for a newer restore point and how would I invoke it?

Thanks for your suggestions.