620MB lost data, share your thoughts

Hi,
if anyone can help with this problem i had id be very grateful.

I run Windows XP Pro Service Pack 2 and basically, i seem to have lost 620MB of data from my computer, but i dont know where from.

I normally keep an eye on my C: drive, to see how much space is left on it. I do this by clicking on properties of the C: drive. Now while i was doing my usual activities (BitComet, 7z, ePSXe, NotePad) i noticed that the space left on the C: drive had suddenly increased by 620MB.

Ive been trying to explain this to myself, what happened? Heres a reconstruction of events:

While extracting some game files, windows complained about there not being enough space on the HD (there was) using a tray balloon, which i closed, but then i noticed an icon in the tray showing like a CD-ROM drive, which afterwards disappeared.
Everytime this disk cleanup program notification came up in the past, i remember i needed to confirm before it did anything. Maybe this time, it was desperately out of space that it started cleaning up automatically.

I then deleted the above mentioned game files and emptied the trash without checking what i was deleting (i was in a rush, and ill never do this again). i had just extracted these files, so the 2 actions of extracting and deleting should have had a net C: space increase/decrease of 0MB.

I then checked the C: properties and there was an extra 620MB of empty space available.

I have had some theories:
1. I deleted some other files by mistake. Though i checked, and it seems i have all of my games. All other files on the computer are too small to add up to 620MB. Maybe i deleted a whole folder of software, but 620MB?

2. The windows disc cleaning utility ran automatically and managed to free up 620MB of space. Though, 620MB seems like a lot of space (but maybe it even compressed files, which i usually dont tick in the select options), AND shrotly afterwards i ran this program manually and managed to free up around 240MB of space. Now wouldnt it have cleared this space on the previous run?

3. As a last guess, im guessing that maybe BItComet preallocates disk space and deleting a failed download task, can free up a lot of space. I experimented a bit, but i couldnt recreate this bitcomet behaviour, if indeed it is possible and/or default.

4. The C: properties were either consistently wrong before this event, or are consistently wrong now. A bit farfetched, but one more doubt.

5. Other reasons which maybe someone can shed some light on...

Heres an extra question:

Is there a way to tell which files have been deleted after ive emptied the trash?

So far ive only done a search for files/folders with date last modified set, but it was kinda vague, supporting the claim that i hadnt deleted anything by accident.

If you need more info, just quickly reply to this and state what info you want.

Thanks for reading (its very long and boring).

I think you haven't lost any important data. It's just Windows's cleaning utility. Maybe you had so much temporary files that Windows managed to delete. If you use IE, then it is likely that it's cache could be that big.

You can check deleted files with programs such Recover4all, and other file recovery (undelete) programs.

Your sure this isnt caused by your windows swap file?

That might be one thing too, if a dynamic swap file is used.

Thanks to GodJonez and Norgus for replying.

Norgus: Im not familiar with anything referred to as "windows swap file", dynamic or not. Do you think that it may give some clues? If so, what could i actually do to gain some insights?

GodJonez: Thanks for the Recover4all info, i tried it and it correctly showed files i had just emptied out of my recycle bin, but more importantly many files from the IE cache, and also from System Recovery Points. Your guess as to the cleanup being responsible seems to be correct.

Yep, the restore points are also included in the cleanup process, and they take lots of space.

Thinking of system restore gobbling up space. If you're running your HD as tight as you are you might want to turn down the amount of your drive it takes, the default setting allows itself 10% o_O I turned mine down to 5% and freed up 4GB and still have restore point going back ages.

I think 5% is more than enough for anyone. You normally use system restore when you made something that really messed up your computer. I've used it a few times in my life, don't disable it or you'll be sorry when you'll need it. :)

i disabled mine. i've been sorry 2 times. its still disabled. :)

I have it enabled on C: drive, in other drives I disabled it. Why would I take space from other drives as there aren't any Windows files in them?

It was probably old system restore stuff... if your comp works fine you shouldn't really worry about it, if it starts going funny simply do a repar install.

The file protection in XP is so intrusive the minute something important gets deleted it'll fill your screen with reminders =)