Hi Barefoot, thank you for replying so quickly.
I had a look at the threads you suggested me and here are some remarks and thoughts about the various actions I took to resolve the problem:
Thread 1 (Crashnet): I do not use diskeeper or 3rd party tools except Acronis for my image backups. I have a scheduled Windows defrag running each Wednesday. So I take that in account when testing. I have some other sheduled tasks running. Some of them could perhaps influence the restore points but I don't know which ones. I shall have a closer look to identify them and inform you.
Thread 2 (Tedredted): my purpose here is not to save image restore points to another location because I need my restore points wherever I might be out of home. I want to make my laptop working as it should in every condition. I make regulary image backups of my system, the problem is that they are so time consuming.
Thread 3 (Jacktenenbaum): set system protection off , all RP's deleted, shutdown and reboot, put protection on, create RP,s shutdown and reboot. No way, all RP's deleted. I have only one c: drive primary NTFS partition.
I did not do the reset of the repository as Capt.JackSparrow suggested. Anyway I am able to make automatic and manual RP's.
Thread 4 (Whoosh7): I made 2 upgrade repairs already with my original Win7 DVD simulating an upgrade. This didn't fix the problem.
Perhaps my disk capacity could be the cause. I have a total of 93Gb from which roughly 16.4GB is free, 9.3GB (10%) is reserved for max snapshot SR. This should be OK as I am not doing image backups with windows. I use Acronis for image backups on external media. Drive C: is formatted in one single primary NTFS partition and contains no backups.
What are the minimum requirements for SR ?
I hope I will not have to erase my disk and reinstall everything.