Clicking Start, Control panel/computer results in "System Call Failed"

A few weeks ago a techie friend tidied up my Vista laptop. Coincidentally a few days later, when I switched on my desktop (windows7) all my documents had disappeared. I reinstalled from a backup.
I do think this must be a coincidence.
However I now find that after working on the desktop for a while, clicking Start and then Control Panel or Computer result in a explorer.exe "System Failled Call" window appearing.
Restarting clears this but it happens again.
I have scanned with AVG & windows defender and also used the microsoft system scan tool. Nothing untoward showed up.
Attempted a system restore but no luck as it wouldn't work.
I ran Task manager, killed explorer.exe, went back into task manager, new task and typed "explorer.exe". This has worked for the moment.
Finally each time I close down I get the message programs are still running tho' none are listed. My only option is to force closedown. I feel these problems are all related.

Incidentally, when another user logged in their closedown was clean.
Very confused. Any help would be appreciated.

I first would create a new Restore Point. Then I would go to MSCONFIG via WinKey--R and either disable some startup items or select Diagnostic Startup. If these stop the problem then focus on what is enabled in a full boot - including non-MS services on the Services tab of MSCONFIG.

Many thanks for your reply. I have deleted programs from start menu and run the ms config as suggested and the problem with non responsive icons appears to be resolved. I still get the 'program still open' message when I attempt to close down but the PCs then closes down within a few minutes. I do not have to forcibly close.
Thanks again for your help

Excellent. Another, and more subtle, place programs can launch from is the Task Scheduler at Control Panel / Admin Tools. Some progs launch there at startup or afterward, and often without asking permission to do so.

Thanks again. I've just looked into admin tools and all processes listed there are dated 2009 so assume not causing the problems.
When I first went to the control panel the "system call failed" window reared its ugly head again this time with a string of hex digits!! Aaaarghh!!
killing explorer.exe in task manager/ processes
ctr/alt/del
running explorer.exe in new task
did the trick but it is a pain.

Do you think I somehow have a corrupt version of explorer.exe? I use aol browser or chrome normally so confused as to why explorer is causing me such grief. Any light thrown on the matter will be very much appreciated

If it's not a third-party program it's time to look at Windows itself. I would try a SFC /scannow in an elevated CMD window. This is how Windows attempts to heal itself. THere's a good tutorial here: SFC /SCANNOW Command - System File Checker

Hi Paul. I have now completed the SFC /SCANNOW command as administrator. All ran okay and found no problems so will have to wait and see if it has helped.
Thanks again for all your help and assistance. Hopefully we are there but watch this space!

Back to square one!!
Again getting the system call failed message a short while after logging on.
I can temporarily fix it but it always seems to come back. Just a pain all round!

I thought this would happen. There seems to be a disparity between other users not seeing the problem, and not finding anything amiss among autoruns for your account.

One other possibility occurs to me - that the account itself is corrupted. If there really is nothing starting up in the background causing this, and if other users consistently do not see this problem, you could create a new account and move your data to it, then delete this one.

Hello again. Ok. I was using the "owner" account but had set an account up in my name with administrator rights so have swapped to that.
Can I delete the "owner" account and then re-establish it? I'm not sure and nervous of trying as I don't want to compromise the number one administrator account. On the other hand I would rather not have the corrupted account on the PC.
Incidentally, own account is functioning perfectly!

Any advice you can give me?
Many thanks for all your assistane to date. I am moving forward!!