oh, so there is no hidden files that store data when i'm playing in the C: drive?
Yes, there is, the page file. It is the alternative slow memory source windows has to use if the PC runs out of actual ram. It is not ideal, as the hard drive is SO much slower than actual ram that WIndows 10 tries to avoid using it at all costs. If you close a program during the day, windows, instead if writing that info back to hdd, compresses the data into ram so that if you open program again, it doesn't have to get it off hdd. But if a program needs all the ram, windows will write the compressed data onto page file
Windows can shrink itself down to tiny amounts and still work, but there is only so far it can go. And it gets really slow if its running off page file.
How slow does it run the game? Your pc has half the minimum ram needed to play so the only way the game could be running is off the page file. Since maximum size of page file can be 4x times ram amount, that would explain the growth.
4gb of ddr2 ram? How much free ram do you have at idle on desktop?
Are you running 32bit or 64bit?
I would hope 64 or you already missing out on 500mb of ram. If you have 64bit, you really need more ram.
So the space it expands on the hdd is 2x your ram size + possibly whatever else was running on PC before you start game up.
More ram would fix the problem of your hdd losing space every time you play
e7400 is only a few years newer than my last pc. I had a P5N32E-SLI with E6600 CPU. I never contemplated putting Win 10 on it. It didn't even have win 8 drivers.
It could also be a bug in game and might get fixed from their end.