Troubleshoot System restore points vanishing

[conceptualclarity]

I have been accustomed to looking in CCleaner and seeing months of old System restore points. I was therefore shocked earlier in the week to see only three. Then a couple of days later I checked, and those three were gone, and I had none at all.

I have not defragged lately. I don't have Windows set to be doing this kind of thing with the points. What could be causing these points to disappear spontaneously? In the past they generally stayed until I deleted them manually.



Computer: DELL Dimension 2400
CPU: Intel Pentium 4-2667 (Northwood, D1)
2666 MHz (20.00x133.3) @ 2658 MHz (20.00x132.9)
Motherboard: DELL 0G1548
Chipset: Intel 845GEV (Brookdale-GEV) + ICH4
Memory: 2048 MBytes @ 166 MHz, 2.5-3-3-7
- 1024 MB PC3200 DDR-SDRAM - Kingston K
- 1024 MB PC3200 DDR-SDRAM - Kingston K
Graphics: Intel 82845G/GL/GV Graphics Controller [DELL]
Intel i845G(L) Integrated, 64 MB
Drive: WL120GPA872, 117.2 GB, E-IDE (ATA-7)
Drive: WDC WD2500JB-57GVC0, 244.2 GB, E-IDE (ATA-6)
Drive: HGST HTS545050A7E380, 488.4 GB, Serial ATA 3Gb/s <-> USB
Drive: SAMSUNG CD-R/RW SW-252S, CD-R Writer
Sound: Intel 82801DB(M) ICH4(-M) - AC'97 Audio Controller [A-1]
Sound: Creative Technology SB Live! Series Audio Processor
Network: RealTek Semiconductor RTL8139 PCI Fast Ethernet NIC [A/B/C]
OS: Microsoft Windows XP Home Edition Build 2600
Antivirus: Panda Antivirus Pro 17.0.1
Firewall: Panda Antivirus Pro 17.0.1
Ad Blocker: Adguard, Ad Muncher, Adblock Plus
Default Browser: Maxthon 4.4.8.1000