Hello all- This may be a Windows issue, but, as you can imagine, I can't get anywhere in the chaos of Windows user forums, nor with Microsoft.
Beginning on a new machine at the beginning of July, once the screensaver is invoked, the only way I can resume my Windows session is to hit control-alt-delete. Simply hitting a key or moving the mouse will not bring the computer out of the screensaver mode. It does stop my SETI screensaver, but the BOINC standby one takes its place. (Please let me know if I could phrase that better and I will edit this post accordingly.)
This was not occurring on my previous machine, which croaked a week before I started using the new one. I presume the Windows build on the new machine was the same as on the old once it connected and updated itself, but I can't say for sure.
I have seen some threads on various forums describing similar behavior, but most or all seem to relate to some Windows photo (slide show?) screensaver function that I assume does not apply here as I have never used any such feature.
To the best of my knowledge, all my drivers are up to date.
Anyone have any ideas what this could be, or where I might look for an answer?
Thanks in advance.
Eric

BOINC 7.12.1 (x64)
Dell XPS Windows 10 version 1803 (build 17134.228)
NVIDIA GeForce GT 610 display adapter
Some event log entries:
9/6/2018 10:46:26 PM | | cc_config.xml not found - using defaults
9/6/2018 10:46:26 PM | | Starting BOINC client version 7.12.1 for windows_x86_64
9/6/2018 10:46:26 PM | | log flags: file_xfer, sched_ops, task
9/6/2018 10:46:26 PM | | Libraries: libcurl/7.47.1 OpenSSL/1.0.2g zlib/1.2.8
9/6/2018 10:46:26 PM | | Data directory: C:\ProgramData\BOINC
9/6/2018 10:46:26 PM | | Running under account E
9/6/2018 10:46:26 PM | | CUDA: NVIDIA GPU 0: GeForce GT 610 (driver version 391.35, CUDA version 9.1, compute capability 2.1, 2048MB, 1684MB available, 156 GFLOPS peak)
9/6/2018 10:46:26 PM | | OpenCL: NVIDIA GPU 0: GeForce GT 610 (driver version 391.35, device version OpenCL 1.1 CUDA, 2048MB, 1684MB available, 156 GFLOPS peak)
9/6/2018 10:46:26 PM | | OpenCL: Intel GPU 0: Intel(R) UHD Graphics 630 (driver version 22.20.16.4758, device version OpenCL 2.1, 3193MB, 3193MB available, 202 GFLOPS peak)
9/6/2018 10:46:26 PM | | OpenCL CPU: Intel(R) Core(TM) i3-8100 CPU @ 3.60GHz (OpenCL driver vendor: Intel(R) Corporation, driver version 7.5.0.550, device version OpenCL 2.1 (Build 550))
9/6/2018 10:46:26 PM | | Host name: EHM-XPS8930
9/6/2018 10:46:26 PM | | Processor: 4 GenuineIntel Intel(R) Core(TM) i3-8100 CPU @ 3.60GHz [Family 6 Model 158 Stepping 11]
9/6/2018 10:46:26 PM | | Processor features: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss htt tm pni ssse3 fma cx16 sse4_1 sse4_2 movebe popcnt aes f16c rdrandsyscall nx lm avx avx2 vmx tm2 pbe fsgsbase bmi1 smep bmi2
9/6/2018 10:46:26 PM | | OS: Microsoft Windows 10: Core x64 Edition, (10.00.17134.00)
9/6/2018 10:46:26 PM | | Memory: 7.82 GB physical, 12.57 GB virtual
9/6/2018 10:46:26 PM | | Disk: 224.44 GB total, 159.07 GB free
9/6/2018 10:46:26 PM | | Local time is UTC -4 hours
9/6/2018 10:46:26 PM | | No WSL found.
9/6/2018 10:46:26 PM | SETI@home | URL http://setiathome.berkeley.edu/; Computer ID 8050566; resource share 100
9/6/2018 10:46:26 PM | SETI@home | General prefs: from SETI@home (last modified 21-Jul-2016 10:16:29)
9/6/2018 10:46:26 PM | SETI@home | Computer location: home
9/6/2018 10:46:26 PM | SETI@home | General prefs: no separate prefs for home; using your defaults
9/6/2018 10:46:26 PM | | Reading preferences override file
9/6/2018 10:46:26 PM | | Preferences:
9/6/2018 10:46:26 PM | | max memory usage when active: 2400.96 MB
9/6/2018 10:46:26 PM | | max memory usage when idle: 7202.88 MB
9/6/2018 10:46:26 PM | | max disk usage: 20.00 GB
9/6/2018 10:46:26 PM | | max CPUs used: 2
9/6/2018 10:46:26 PM | | don't compute while active
9/6/2018 10:46:26 PM | | don't use GPU while active
9/6/2018 10:46:26 PM | | (to change preferences, visit a project web site or select Preferences in the Manager)
9/6/2018 10:46:26 PM | | Setting up project and slot directories
9/6/2018 10:46:26 PM | | Checking active tasks
9/6/2018 10:46:26 PM | SETI@home | Task 04dc10aa.23919.13564.3.30.233_0 is 729.70 days overdue; you may not get credit for it. Consider aborting it.
9/6/2018 10:46:26 PM | SETI@home | Task 16dc08aa.17304.25021.7.34.112_0 is 442.18 days overdue; you may not get credit for it. Consider aborting it.
9/6/2018 10:46:26 PM | | Setting up GUI RPC socket
9/6/2018 10:46:26 PM | | Checking presence of 86 project files
9/6/2018 10:46:26 PM | | Suspending computation - computer is in use
9/6/2018 10:46:26 PM | | Suspending network activity - computer is in use
9/6/2018 11:06:41 PM | | Resuming network activity
9/6/2018 11:37:29 PM | | Suspending computation - computer is in use
9/6/2018 11:37:29 PM | | Suspending network activity - computer is in use
9/6/2018 11:44:46 PM | | Windows is suspending operations
9/7/2018 6:58:54 AM | | Resuming after OS suspension
9/7/2018 6:58:54 AM | | Resuming computation
9/7/2018 6:58:55 AM | | Resuming network activity
9/7/2018 6:58:56 AM | | Windows is resuming operations
9/7/2018 6:59:11 AM | | Suspending computation - computer is in use
9/7/2018 6:59:11 AM | | Suspending network activity - computer is in use
9/7/2018 7:10:19 AM | | Resuming computation
9/7/2018 7:10:19 AM | | Resuming network activity
9/7/2018 7:23:26 AM | | Suspending computation - computer is in use
9/7/2018 7:23:26 AM | | Suspending network activity - computer is in use
9/7/2018 7:44:06 AM | | Resuming computation
9/7/2018 7:44:06 AM | | Resuming network activity
9/7/2018 7:49:09 AM | SETI@home | Sending scheduler request: To fetch work.
9/7/2018 7:49:09 AM | SETI@home | Requesting new tasks for Intel GPU
9/7/2018 7:49:12 AM | SETI@home | Scheduler request completed: got 1 new tasks
9/7/2018 7:49:14 AM | SETI@home | Started download of blc16_2bit_guppi_58227_11799_HIP53117_0031.30537.818.22.45.136.vlar
9/7/2018 7:49:17 AM | SETI@home | Finished download of blc16_2bit_guppi_58227_11799_HIP53117_0031.30537.818.22.45.136.vlar
9/7/2018 7:49:27 AM | SETI@home | Computation for task 04se18aa.26044.13977.15.42.16.vlar_1 finished
9/7/2018 7:49:27 AM | SETI@home | Starting task blc16_2bit_guppi_58227_11799_HIP53117_0031.30537.818.22.45.136.vlar_0
9/7/2018 7:49:30 AM | SETI@home | Started upload of 04se18aa.26044.13977.15.42.16.vlar_1_r920742181_0
9/7/2018 7:49:33 AM | SETI@home | Finished upload of 04se18aa.26044.13977.15.42.16.vlar_1_r920742181_0
9/7/2018 7:53:02 AM | | Suspending computation - computer is in use
9/7/2018 7:53:02 AM | | Suspending network activity - computer is in use
9/7/2018 8:05:11 AM | | Resuming computation
9/7/2018 8:05:11 AM | | Resuming network activity

As I unfortunately cannot edit my original post, I have to add a note here with something I omitted from it:
After hitting ctrl-alt-del, you have to hit "cancel" on the next screen to get back into the Windows session.