Nogo on the safemode, I didn't think there would but it eliminates memory and other programs being an issue. You've done everything you can while still maintaining your sanity. At least you can downgrade until coast is clear.
By saying, "You have enough memory," I meant that 1GB RM should be enough memory to prevent slim from crashing with no other heavy programs running. Your performance meter seems to agree. You were pushin it, but no major stress.
Virtual memory is OS simulated RAM running on the hard drive. Looks like RAM to the program, runs 100 times slower than physical RAM but it prevents crashes from running out of memory. Set it to allow Windows to manage virtual memory automatically. Then it will use as little as possible, but can increase instantly if needed. It should take a couple GB or so if you have it to spare.
My kids use an XP SP3 machine with 1.5GB, memory is maxed out. It is a little slow to fully boot, but once it's up and running it's fast enough for the kids playing online VR action games like Roblox and Wizard101. You can check how much physical RAM you have in system properties, then look it up on 4allmemory.com to see if it's worth maxing it out. Some commodity memory is really cheap now. I still have a 500MB DIMM lying around unused. It's yours if you want it, goes in Dell Dimension 2400, probably pretty standard DIMM, you can look it up on 4allmemory to know for sure. Win + Break brings up system properties, or right click My Computer icon for properties command.