System Restore not working

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: Intel(R) Pentium(R) CPU P6200 @ 2.13GHz, Intel64 Family 6 Model 37 Stepping 5
Processor Count: 2
RAM: 7862 Mb
Graphics Card: Intel(R) HD Graphics, -292 Mb
Hard Drives: C: Total - 610480 MB, Free - 147187 MB; E: Total - 1907695 MB, Free - 39636 MB;
Motherboard: Acer, Aspire 5733Z
Antivirus: ESET Smart Security 7.0, Updated and Enabled

System Restore won't work on this machine - it keeps switching itself off.

If I go to the System Restore settings, I can switch it on and create a restore point. The restore point is then shown if I immediately check the list of available restore points.

After a short period of time, e.g. 20 minutes, checking the System Restore settings shows that it's switched off and my restore point has disappeared.

Any ideas welcome.

Thanks